ISSN 1359-7345

COMMUNICATION Jian Zhang, Guofu Zhong et al . Iridium-catalyzed alkenyl C–H allylation using conjugated dienes

ChemCommChemical Communicationsrsc.li/chemcomm

Volume 55 Number 66 25 August 2019 Pages 9735–9882

This journal is©The Royal Society of Chemistry 2019 Chem. Commun., 2019, 55, 9757--9760 | 9757

Cite this:Chem. Commun., 2019,

55, 9757

Iridium-catalyzed alkenyl C–H allylation usingconjugated dienes†

Liangyao Xu, Keke Meng, Jian Zhang, * Yaling Sun, Xiunan Lu, Tingyan Li,Yan Jiang and Guofu Zhong*

An iridium-catalyzed C–H allylation of acrylamides with conjugated

dienes was developed, using NH-Ts amide as the directing group.

The ligand- and additive-free protocol provided a convenient and

atom economic synthesis of branched 1,4-diene skeletons, enabling

the tolerance of a wide scope of functionalities such as OMe, F, Cl,

Br and CF3. The utility of this protocol is also demonstrated by a

preparative scale, as well as C–H functionalization of artemisic amide.

Furthermore, NH-Ts amide was efficiently removed by methylation

and hydrolysis procedures to provide 1,4-dienoic acid.

Skipped dienes (1,4-dienes) represent ubiquitous componentsin countless biologically active molecules such as jerangolid,ripostatin and biselyngbyolide analogues (Scheme 1).1 They arealso versatile synthetic building blocks in synthetic organicchemistry.2 Consequently, many powerful synthetic methodshave been developed for the construction of 1,4-dienes,3–7 includingcatalytic cross-couplings,4 ene reactions,5 olefinations,6 as wellas Morita–Baylis–Hillman reactions.7 Despite their effectiveness,developing regio-/stereo-selective, practical and atom economicsynthesis of structurally diverse 1,4-dienes from readily availablestarting materials still remains a challenge.

Recently, direct C–H allylation of aromatic or alkyl C–H bondscatalyzed by transition metal catalysis has attracted much attentionin terms of synthetic and atom efficiency.8 Remarkable progresshas been made in alkenyl C–H alkenylation via metallocycleintermediates, leading to valuable 1,3-diene derivatives.9 In con-trast, there are limited examples of directed alkenyl C–H allylationto provide versatile 1,4-dienes,10 presumably due to thermodyna-mically controlled olefin isomerization.11 The Loh group developeda rhodium(III)-catalyzed C–H allylation of electron-deficient alkeneswith allyl acetates.10a You and co-workers described the directallylation of o-amino styrenes with allylic carbonates, affording

skipped (Z/E)-dienes with the exclusive formation of a cis doublebond.10c However, these protocols employed various olefinsbearing allylic surrogates to be proceeded via the b-O or b-Xelimination over b-H elimination with the liberation of by-products such as acetic acid and CO2. Moreover, the substratescope of these methods usually suffered from poor selectivityand/or limited reactivity when applied to the synthesis ofbranched and multi-substituted skipped dienes.

Conjugated dienes (1,3-dienes) are widely recognized synthonsin synthetic chemistry,9,12 and there have been examples ofallylation using 1,3-dienes.13 However, very limited exampleshave been reported on direct alkenyl C–H allylation usingconjugated dienes with atomic economy, providing site- andstereo-selective preparation of skipped dienes.14 Recently, the Chirikgroup reported a selective [1,4]-hydrovinylation of 1,3-dieneswith inactivated olefins enabled by iron diimine catalysts.14a

RajanBabu also demonstrated a cobalt-catalyzed enantioselectivehetero-dimerization of acrylates and 1,3-dienes.14b

Compared to the remarkable progress made in Ir-catalyzedaromatic C–H functionalizations,15 examples of alkenyl C–Hfunctionalization continue to be scarce,10c,16 presumably due tothe lability of alkenes under highly active iridium catalysis.Furthermore, competitive C(alkenyl)–H and C(allyl)–H cleavagesites, as well as ready alkene isomerisation, can make alkenyl

Scheme 1 Alkenyl C–H allylation by iridium catalysis.

College of Materials, Chemistry and Chemical Engineering, Hangzhou Normal

University, Hangzhou 311121, China. E-mail: zhangjian@hznu.edu.cn,

zgf@hznu.edu.cn

† Electronic supplementary information (ESI) available: Detailed experimentalprocedures and analytical data. See DOI: 10.1039/c9cc04419a

Received 9th June 2019,Accepted 18th July 2019

DOI: 10.1039/c9cc04419a

rsc.li/chemcomm

ChemComm

COMMUNICATION

Publ

ishe

d on

29

July

201

9. D

ownl

oade

d by

TH

E L

IBR

AR

Y O

F H

AN

GZ

HO

U N

OR

MA

L U

NIV

ER

SIT

Y o

n 8/

16/2

019

9:58

:16

AM

.

View Article OnlineView Journal | View Issue

9758 | Chem. Commun., 2019, 55, 9757--9760 This journal is©The Royal Society of Chemistry 2019

C–H allylation a significant challenge.11,15,16 Given the importanceof 1,4-dienes and our continuous interest in chelation-assistedalkenyl C–H functionalization,9e–h herein, we focus on the iridium-catalyzed alkenyl C–H allylation using conjugated dienes toselectively construct branched skipped dienes (Scheme 1).

The initial optimization experiments were performed withN-Ts acrylamide (Ts = p-toluenesulfonyl, 1a) and 1-phenyl-1,3-butadiene (2a), catalyzed by various iridium complexes. It issupposed that the deprotonation of N-sulfonyl acrylamidebearing an acidic N–H bond with the iridium complex givesan amidoiridium(I) species, serving as a key intermediate for thesubsequent C–H activation and alkene migratory insertion.15n–p

Various iridium complexes were examined using methanol asa solvent. Although [IrCp*Cl2]2 exhibited no catalytic activity,[IrCl(COD)]2 led to 3aa in 54% yield (Table 1, entries 1 and 2).Next, other iridium complexes bearing a 1,5-cyclooctadiene (COD)ligand were examined. Much to our delight, both [Ir(cod)]BF4 and[IrOMe(cod)]2 greatly promoted the reaction, leading to 3aa in 83%and 90% yields respectively (entries 3 and 4). Other representativesolvents such as toluene, DCE, MeCN, dioxane, DME, and hexanecould not further improve the reaction with [IrOMe(cod)]2 (entries5–10). Notably, cross-coupling even proceeded in water, albeit withreduced yield (entry 11). Decreasing the amount of [IrOMe(cod)]2 to1.0 mol% also led to satisfactory results with longer reaction time(entry 12). In contrast, neither [RhCp*Cl2]2 nor [Ru( p-cymene)Cl2]2exhibited catalytic reactivity, although both of them were robust inC–H functionalizations (entries 13 and 14).9 A palladium complexsuch as Pd(OAc)2 also showed no efficacy (entry 15).

With the optimized catalytic conditions in hand, we nextexamined the scope of this amide directed alkenyl C–H allyla-tion reaction (Table 2). Firstly, representative aliphatic and

aromatic group tethered a- and/or b-substituted acrylamides1a–1n were investigated. Installation of long alkyl chains to thea-position of acrylamides still led to excellent yields (3ba and3ca). Benzyl substituted acrylamide 1d reacted successfully toprovide 3da in 74% yield, and no olefin isomerization wasobserved. Aromatic acrylamides bearing sensitive F, Cl, CF3,and OMe gave the corresponding products in 50–80% yields,thus exhibiting good functional-group compatibility (3ea–3ja).While angelic acid derived amide 1k led to 58% yield, acrylamideembedded with a cyclopentenyl or cyclohexenyl unit produced 3laor 3ma in excellent yield. However, b-substituted acrylamide 1nshowed limited reactivity, with the formation of an inseparableconjugated diene by olefin isomerization (3na and 3na0). Differ-ently N-substituted acrylamides were also investigated. The reac-tion of N-Ms substituted acrylamide (Ms = methysulfonyl, 1o)that was converted smoothly provides 3oa in 83% yield. Not onlyN-sulfonylamides but also some other amides bearing acidic N–Hbonds were capable of undergoing the C–H allylation. Acryl-amides bearing NH-OMe were efficiently converted, leading tomethyl or phenyl 1,4-dienes in excellent yield (3pa and 3qa). Incontrast, NH-Me substituted acrylamide 1r bearing a less acidicN–H bond provided the allylation product in only 17% yield due

Table 1 Optimization of catalytic conditionsa

Entry Catalyst Solvent Yieldb (%)

1 [IrCp*Cl2]2 MeOH 02 [IrCl(cod)]2 MeOH 543 [Ir(cod)2]BF4 MeOH 834 [IrOMe(cod)]2 MeOH 905 [IrOMe(cod)]2 Toluene 896 [IrOMe(cod)]2 DCE 797 [IrOMe(cod)]2 MeCN 698 [IrOMe(cod)]2 Dioxane 849 [IrOMe(cod)]2 DME 8410 [IrOMe(cod)]2 Hexane 5411 [IrOMe(cod)]2 H2O 5412c [IrOMe(cod)]2 MeOH 8413 [RhCp*Cl2]2 MeOH 014 [Ru(p-cymene)Cl2]2 MeOH 015 Pd(OAc)2 MeOH 0

a Unless otherwise noted, the reactions were carried out using acrylamide1a (0.24 mmol), diene 2a (0.2 mmol), [Ir] (10 mol%), in a solvent (0.2 M,1.0 mL) at 70 1C for 16 h under an argon atmosphere (1 atm). b The yieldsindicated in the table are isolated yields. c 1.0 mol% [IrOMe(cod)]2 wasused, 48 h. DCE = 1,2-dichloroethane; DME = 1,2-dimethoxyethane.

Table 2 Substrate scopea

a Unless otherwise noted, the reactions were carried out using acryl-amide 1 (0.24 mmol), diene 2 (0.2 mmol), [IrOMe(cod)]2 (5 mol%), inMeOH (0.2 M) at 70 1C for 16 h under an argon atmosphere (1 atm). Theyields are isolated yields.

Communication ChemComm

Publ

ishe

d on

29

July

201

9. D

ownl

oade

d by

TH

E L

IBR

AR

Y O

F H

AN

GZ

HO

U N

OR

MA

L U

NIV

ER

SIT

Y o

n 8/

16/2

019

9:58

:16

AM

. View Article Online

This journal is©The Royal Society of Chemistry 2019 Chem. Commun., 2019, 55, 9757--9760 | 9759

to low reactivity (3ra). These results exhibited the key effect ofacidic N–H bonds in the catalytic C–H allylation reaction.17

A variety of conjugated dienes were examined to give thecorresponding 1,4-diene products. Olefinic C–H allylationusing aliphatic diene 2b still proceeded well, giving 3ab in69% yield, without the formation of any other isomers by olefinmigration.11 The reactions of 1-aryl-1,3-butadienes bearing F,Br and OMe led to products 3ac–3af in 89–94% yields, regardlessof their electron-withdrawing or electron-donating properties.Significantly, the protocol was extended to heterocycles such asfuran, which provided 3ag in good yield. Introduction of a largearomatic ring such as anthracene into the diene also led to 3ah in78% yield. The reaction of an internal diene 2i proceeded withhigh regioselectivity to give 3ai, albeit with lower yield. Notably,branched butadienes such as 2-methyl-1-phenyl-1,3-butadiene stillconverted well to give 3aj in moderate yield. Aromatic acrylamide1e also gave the products 3ec and 3ef in excellent yields.18

Considering the remarkable catalytic efficacy of the iridium-catalyzed cross-couplings, we attempted to gain some preliminaryunderstanding of the reaction mechanisms. Competition experi-ments between acrylamides 1j and 1g revealed the more electron-deficient acrylamide to be converted preferentially, hence renderingan electrophilic C–H bond activation less likely to be operative(Scheme 2a). These results are consistent with prior observationsin ruthenium- or rhodium-catalyzed C–H alkenylation.9 Intermo-lecular competition experiments between dienes 2f and 2c high-lighted the electron-deficient one to be more reactive (Scheme 2b).

The results of deuterium-labeling experiments provided uswith mechanistic insights (Scheme 3). If substrate 1e wastreated with CD3OD under iridium catalysis, deuterium scram-bling was observed at both cis and trans alkenyl C–H bonds(Scheme 3a). Reaction of 1e with diene 2a in the presence of[Ir(OMe)(cod)]2 (5 mol%) in CD3OD (0.2 M) at 70 1C for 11 mingave product 3ea in 42% yield, where deuterium incorporationwas observed for 3ea as well as recovered 1e and 2a (Scheme 3b).19

These results indicated C–H activation and hydro-metalationsteps to be fast and reversible, and the reductive elimination stepdetermines the regioselectivity.15

The scalability of the process is demonstrated by the allylation ofacrylamide 1a with diene 2a on a gram scale, which produced 3aa in90% yield using only a 2.5 mol% Ir-catalyst (Scheme 4a). The amidegroup can be conveniently removed by methylation and then hydro-lysis procedures, providing carboxylic acid 4 without any erosion ofthe Z/E configuration (Scheme 4b). A particularly useful applicationof this mild protocol is in the late-stage C–H functionalization ofbioactive molecules such as artemisic acid derived amides, leadingto alkenylation analogue 3sa in good yield (Scheme 4c). So, weexpect our methodology to provide valuable opportunities to accele-rate structure–activity relationship studies in drug discovery.

The possible catalytic cycle is postulated as illustrated inScheme 5. A methoxoiridium complex reacts with acrylamide1 to form amidoiridium(I) species A. Oxidative addition of avicinal C(alkenyl)–H bond to iridium gives hydridoiridium(III)intermediate B, which reacts with 1,3-diene 2 to generatep-allyliridium(III) species C by a branch-selective alkene insertion.Irreversible reductive elimination from allyliridium C and ligandexchange by acrylamide 1 give the corresponding branched 1,4-diene 3 and regenerate amidoiridium species A. On the otherhand, a linear selective alkene insertion into the Ir–H bondproceeds to form E which does not undergo reductive elimina-tion and returns to B via b-hydrogen elimination. The regioselec-tivity is controlled by a combination of electronic and stericeffects in the migratory insertion of dienes into the Ir–C(alkenyl)bond.15,20 An alternative reaction pathway involves alkene inser-tion into an Ir–C bond (metallocycle intermediate F) and reduc-tive elimination of the C–H bond was less likely to occur.21

In conclusion, we have developed an iridium-catalyzed alkenylC–H allylation reaction between acrylamides and conjugateddienes. With the assistance of a NH-Ts amide, this allylationprocess enables mild and atom economic preparation of branched1,4-dienes with excellent regio- and stereo-selectivities. The addi-tive- and ligand-free protocol is applicable to a broad range ofacrylamides and conjugated diene substrates, displaying a widefunctional group tolerance. The utility of this protocol is alsodemonstrated by the preparative scale, as well as late-stage C–Hfunctionalization of artemisic amides. Furthermore, dienamidewas efficiently converted to 1,4-dienoic acid by removal of NH-Tsamide under methylation/hydrolysis conditions, indicating thegreat synthetic value of this protocol.

We gratefully acknowledge the National Natural ScienceFoundation of China (NSFC) (21502037 and 21672048), the

Scheme 2 Intermolecular competition experiments.

Scheme 3 Deuterium-labeled experiments. Scheme 4 Synthetic applications.

ChemComm Communication

Publ

ishe

d on

29

July

201

9. D

ownl

oade

d by

TH

E L

IBR

AR

Y O

F H

AN

GZ

HO

U N

OR

MA

L U

NIV

ER

SIT

Y o

n 8/

16/2

019

9:58

:16

AM

. View Article Online

9760 | Chem. Commun., 2019, 55, 9757--9760 This journal is©The Royal Society of Chemistry 2019

Natural Science Foundation of Zhejiang Province (ZJNSF)(LY19B020006), and the Pandeng Plan Foundation of HangzhouNormal University for Youth Scholars of Materials, Chemistryand Chemical Engineering for financial support.

Conflicts of interest

There are no conflicts to declare.

Notes and references1 (a) Y. Shinohara, F. Kudo and T. Eguchit, J. Am. Chem. Soc., 2011,

133, 18134; (b) P. Winter, W. Hiller and M. Christmann, Angew. Chem.,Int. Ed., 2012, 51, 3396; (c) W. Tang and E. V. Prusov, Angew. Chem.,Int. Ed., 2012, 51, 3401; (d) F. Lindner, S. Friedrich and F. Hahn,J. Org. Chem., 2018, 83, 14091; (e) H. Irschik, H. Augustiniak, K. Gerth,G. Hofle and H. Reichenbach, J. Antibiot., 1995, 48, 787; ( f ) S. Das,D. Paul and R. K. Goswami, Org. Lett., 2016, 18, 1908.

2 (a) J. M. Roulet, B. Deguin and P. Vogel, J. Am. Chem. Soc., 1994,116, 3639; (b) S. E. Denmark, V. Guagnano, J. A. Dixon and A. Stolle,J. Org. Chem., 1997, 62, 4610; (c) S. GowriSankar, C. G. Lee andJ. N. Kim, Tetrahedron Lett., 2004, 45, 6949.

3 S. Durand, J.-L. Parrain and M. Santelli, J. Chem. Soc., Perkin Trans. 1,2000, 253.

4 Cross-couplings: (a) J. Y. Hamilton, D. Sarlah and E. M. Carreira,J. Am. Chem. Soc., 2013, 135, 994; (b) M. S. McCammant, L. Liao andM. S. Sigman, J. Am. Chem. Soc., 2013, 135, 4167; (c) J. Y. Hamilton,D. Sarlah and E. M. Carreira, J. Am. Chem. Soc., 2014, 136, 3006;(d) D. P. Todd, B. B. Thompson, A. J. Nett and J. Montgomery, J. Am.Chem. Soc., 2015, 137, 12788; (e) M. Hirano, ACS Catal., 2019,9, 1408; ( f ) S. Parisotto and A. Deagostino, Org. Lett., 2018, 20, 6891.

5 Ene reaction: (a) S. J. Sturla, N. M. Kablaoui and S. L. Buchwald, J. Am.Chem. Soc., 1999, 121, 1976; (b) B. B. Snider, Acc. Chem. Res., 1980, 13, 426.

6 Olefination: (a) M. J. Schnermann, F. A. Romero, I. Hwang,E. Nakamaru-Ogiso, T. Yagi and D. L. Boger, J. Am. Chem. Soc., 2006,128, 11799; (b) J. Pospısil and I. E. Marko, J. Am. Chem. Soc., 2007,129, 3516; (c) W. B. Liu, H. He, L. X. Dai and S. L. You, Chem. – Eur. J.,2010, 16, 7376; (d) J. Gagnepain, E. Moulin and A. Furstner, Chem. –Eur. J., 2011, 17, 6964; (e) S. Xu, S. Zhu, J. Shang, J. Zhang, Y. Tang andJ. Dou, J. Org. Chem., 2014, 79, 3696; ( f ) X.-T. Ma, Y. Wang, R.-H. Dai,C.-R. Liu and S.-K. Tian, J. Org. Chem., 2013, 78, 11071.

7 (a) D. Basavaiah, N. Kumaragurubaran and D. S. Sharada, Tetrahe-dron Lett., 2001, 42, 85; (b) D. Basavaiah, D. S. Sharada,N. Kumaragurubaran and R. M. Reddy, J. Org. Chem., 2002, 67, 7135.

8 (a) N. K. Mishra, S. Sharma, J. Park, S. Han and I. S. Kim, ACS Catal., 2017,7, 2821; (b) D. Kumar, S. R. Vemula, N. Balasubramanian and G. R. Cook,Acc. Chem. Res., 2016, 49, 2169; (c) P. Koschker and B. Breit, Acc. Chem. Res.,2016, 49, 1524; (d) S. Krautwald, M. A. Schafroth, D. Sarlah andE. M. Carreira, J. Am. Chem. Soc., 2014, 136, 3020; (e) Q. Cheng, H.-F. Tu,C. Zheng, J.-P. Qu, G. Helmchen and S.-L. You, Chem. Rev., 2019, 119, 1855.

9 (a) T. Besset, N. Kuhl, F. W. Patureau and F. Glorius, Chem. – Eur. J.,2011, 17, 7167; (b) X.-H. Hu, J. Zhang, X.-F. Yang, Y.-H. Xu andT.-P. Loh, J. Am. Chem. Soc., 2015, 137, 3169; (c) Q.-J. Liang, C. Yang,F.-F. Meng, B. Jiang, Y.-H. Xu and T.-P. Loh, Angew. Chem., Int. Ed.,2017, 56, 5091; (d) B. Jiang, M. Zhao, S.-S. Li, Y.-H. Xu and T.-P. Loh,Angew. Chem., Int. Ed., 2018, 57, 555; (e) C. Yu, F. Li, J. Zhang andG. Zhong, Chem. Commun., 2017, 53, 533; ( f ) T. Li, J. Zhang, C. Yu,X. Lu, L. Xu and G. Zhong, Chem. Commun., 2017, 53, 12926;(g) C. Yu, J. Zhang and G. Zhong, Chem. Commun., 2017, 53, 9902;(h) F. Li, C. Yu, J. Zhang and G. Zhong, Org. Lett., 2016, 18, 4582.

10 (a) C. Feng, D. Feng and T.-P. Loh, Chem. Commun., 2015, 51, 342;(b) S. Sharma, S. H. Han, Y. Oh, N. K. Mishra, S. Han, J. H. Kwak,S.-Y. Lee, Y. H. Jung and I. S. Kim, J. Org. Chem., 2016, 81, 2243;(c) H. He, W.-B. Liu, L.-X. Dai and S.-L. You, J. Am. Chem. Soc., 2009,131, 8346; (d) W. Yu, W. Zhang, Y. Liu, Z. Liu and Y. Zhang, Org. Chem.Front., 2017, 4, 77; (e) X. Wu and H. Ji, J. Org. Chem., 2018, 83, 12094.

11 We have previously developed a chelation-assisted alkenyl C–Halkenylation via isomerization of 1,4-diene to thermodynamicallystable 1,3-diene, see ref. 9h and F. Li, C. Shen, J. Zhang, L. Wu,X. Zhuo, L. Ding and G. Zhong, Adv. Synth. Catal., 2016, 358, 3932.

12 (a) N. Momiyama, H. Tabuse, H. Noda, M. Yamanaka, T. Fujinami,K. Yamanishi, A. Izumiseki, K. Funayama, F. Egawa, S. Okada, H. Adachiand M. Terada, J. Am. Chem. Soc., 2016, 138, 11353; (b) M. S. McCammant,L. Liao and M. S. Sigman, J. Am. Chem. Soc., 2013, 135, 4167.

13 (a) S. E. Korkis, D. J. Burns and H. W. Lam, J. Am. Chem. Soc., 2016,138, 12252; (b) M. Nagamoto, H. Yorimitsu and T. Nishimura, Org. Lett.,2018, 20, 828; (c) C. C. Roberts, D. M. Matıas, M. J. Goldfogel andS. J. Meek, J. Am. Chem. Soc., 2015, 137, 6488; (d) N. J. Adamson,K. C. E. Wilbur and S. J. Malcolmson, J. Am. Chem. Soc., 2018, 140, 2761.

14 (a) V. A. Schmidt, C. R. Kennedy, M. J. Bezdek and P. J. Chirik, J. Am.Chem. Soc., 2018, 140, 3443; (b) S. M. Jing, V. Balasanthiran, V. Pagar,J. C. Gallucci and T. V. RajanBabu, J. Am. Chem. Soc., 2017, 139, 18034;(c) Y. Sun and G. Zhang, Chin. J. Chem., 2018, 36, 708; (d) M. Kimura andY. Tamaru, Top. Curr. Chem., 2007, 279, 173; (e) Y. Hiroi, N. Komine,S. Komiya and M. Hirano, Organometallics, 2014, 33, 6604.

15 (a) J. Kim, S.-W. Park, M.-H. Baik and S. Chang, J. Am. Chem. Soc., 2015,137, 13448; (b) S. Pan and T. Shibata, ACS Catal., 2013, 3, 704; (c) H. Kimand S. Chang, ACS Catal., 2015, 5, 6665; (d) J. Xia, X. Yang, Y. Li andX. Li, Org. Lett., 2017, 19, 3243; (e) L. Xu, L. Wang, Y. Feng, Y. Li, L. Yangand X. Cui, Org. Lett., 2017, 19, 4343; ( f ) P. Becker, R. Pirwerdjan andC. Bolm, Angew. Chem., Int. Ed., 2015, 54, 15493; (g) K. Shin, Y. Park,M.-H. Baik and S. Chang, Nat. Chem., 2018, 10, 218; (h) F. Romanov-Michailidis, B. D. Ravetz, D. W. Paley and T. Rovis, J. Am. Chem. Soc.,2018, 140, 5370; (i) H. L. Li, Y. Kuninobu and M. Kanai, Angew. Chem.,Int. Ed., 2017, 56, 1495; ( j) E. Erbing, A. Sanz-Marco, A. Vazquez-Romero, J. Malmberg, M. J. Johansson, E. Gomez-Bengoa andB. Martın-Matute, ACS Catal., 2018, 8, 920; (k) G. Tan, Q. You andJ. You, ACS Catal., 2018, 8, 8709; (l) D. F. Fernandez, C. A. B. Rodrigues,M. Calvelo, M. Gulıas, J. L. Mascarenas and F. Lopez, ACS Catal., 2018,8, 7397; (m) M. Yu, T. Zhang, H. B. Jalani, X. Dong, H. Lu and G. Li, Org.Lett., 2018, 20, 4828; (n) Y. Ebe, M. Onoda, T. Nishimura andH. Yorimitsu, Angew. Chem., Int. Ed., 2017, 56, 5607;(o) M. Nagamoto, J. Fukuda, M. Hatano, H. Yorimitsu andT. Nishimura, Org. Lett., 2017, 19, 5952; (p) M. Hatano, Y. Ebe,T. Nishimura and H. Yorimitsu, J. Am. Chem. Soc., 2016, 138, 4010.

16 Amidation, see: (a) H. Kim, G. Park, J. Park and S. Chang, ACS Catal.,2016, 6, 5922; borylation, see: (b) I. Sasaki, J. Taguchi, H. Doi, H. Itoand T. Ishiyama, Chem. – Asian J., 2016, 11, 1400; arylation, see:(c) P. Gao, L. Liu, Z. Shi and Y. Yuan, Org. Biomol. Chem., 2016,14, 7109; deuteration, see: (d) J. Zhou and J. F. Hartwig, Angew.Chem., Int. Ed., 2008, 47, 5783.

17 Neither N-Me-N-Ts nor N,N-dimethyl acrylamide showed reactivityunder catalytic conditions.

18 Unfortunately, neither isoprene nor ethyl sorbate was reactive in thepresent reaction.

19 If the reaction was performed for 12 hours, 13% D at the allylicposition of 3ea (82% yield) was observed (see the ESI† for details).

20 (a) G. Huang and P. Liu, ACS Catal., 2016, 6, 809; (b) S. Grelaud,P. Cooper, L. J. Feron and J. F. Bower, J. Am. Chem. Soc., 2018, 140, 9351.

21 Neither styrene nor butyl acrylate showed reactivity toward acryl-amide; no olefinic C–H vinylation adducts 30 via b-hydride elimina-tion from carbometalation intermediate F were observed (Scheme 5).These results also support a direct addition of Ir–H species to alkeneby the p-allyliridium(III) intermediate.

Scheme 5 Plausible mechanism.

Communication ChemComm

Publ

ishe

d on

29

July

201

9. D

ownl

oade

d by

TH

E L

IBR

AR

Y O

F H

AN

GZ

HO

U N

OR

MA

L U

NIV

ER

SIT

Y o

n 8/

16/2

019

9:58

:16

AM

. View Article Online