JOC Year in Review: 1994 Baran Group Meeting Leah Simke · Forrest Gump Top 5 Most Cited ......

JOC Year in Review: 1994Baran Group Meeting Leah Simke

Statistics:Volume 59Issues 1-268315 pages

Publication Record:

Marshall, J A (13)Adam, W (10)Paquette, L A (10)Denmark, S E (9)Katritzky, A R (8)Padwa, A (8)Rapoport, H (8)Brown, H C (6)Danishefsky, S J (6)de Kimpe, N (5)

Ishii, Y (5)Kumar, A (5)Kurth, M J (5)Liebeskind, L S (5)Matsumoto, K (5)Miller, M J (5)Mori, M (5)Pettit, G R (5)Rozen, S (5)Sato, Y (5)

Notable Events of 1994:Jan 1st - AAPL was $1.04Jan 10th - Lorena Bobbitt's trial begins Mar 31st - Nature reports the finding in Ethiopia of the first complete Australopithecus afarensis skullApr 7th - Vatican acknowledges Holocaust for 1st timeApr 22nd - In Denmark the largest lollipop, weighing 3,011 pounds, madeMay 10th - Nelson Mandela sworn in as South Africa's 1st black presidentJun 15th - Ruth Bader Ginsburg, sworn in as Supreme Court JusticeJun 26th - 126°F (52.2°C) in Death Valley, CalifNov 9th - The chemical element Darmstadtium is discovered.

Top Songs:The Sign by Ace of BaseI Swear by All-4-OneI'll Make Love To You by Boyz II Men

Top Movies:The Shawshank RedemptionPulp FictionForrest Gump

Top 5 Most Cited Papers:

A Practical Method for the Large-Scale Preparation of [N,N'-Bis(3,5-di-tertbutylsalicylidene)-1,2-cyclohexanediaminato(2-)]manganese(III) chloride, a Highly Enantioselective Epoxidation CatalystJay F. Larrow, Eric N. Jacobsen, Yun Gao, Yaping Hong, Xiaoyi Nie, Charles M. Zepp642 citations

On the Nature of the "Copper Effect" in the Stille Cross-CouplingVittorio Farina, Suresh Kapadia, Bala Krishnan, Chenjie Wang, Lanny S. Liebeskind395 citations

Lanthanide Triflates as Water-Tolerant Lewis Acids. Activation of Commercial Formaldehyde Solution and Use in the Aldol Reaction of Silyl Enol Ethers with Aldehydes in Aqueous MediaShu Kobayashi, Iwao Hachiya345 citations

Acceleration of the Dess-Martin Oxidation by WaterStephanie D. Meyer, Stuart L. Schreiber328 citations

Cationic BINAP-Ru(II) Halide Complexes: Highly Efficient Catalysts for Stereoselective Asymmetric Hydrogenation of .alpha.- and .beta.-Functionalized KetonesKazushi Mashima, Koh-hei Kusano, Naomasa Sato, Yoh-ichi Matsumura, Kyoko Nozaki, Hidenori Kumobayashi, Noboru Sayo, Yoji Hori, Takero Ishizaki288 citations


Select Natural Products Isolated Pentalenene104, Burnell

MeMe Et Me

Me Et

OO

MeMe Et

O O(CH2OH)2p-TsOH BF3•Et2O OMe

MeMe

EtO

OMe

MeMe

H

H

4 steps H

H

+ diast.

KOtBu

Me

+ diast.Me

Me

MeH

H

MeH3 steps

pentalenene

OTMSTMSO

CC-1065 (protected A unit)192, Tietze

NH

N

O

NHN

Me

O

OMeOH

O

NH

NH

OMe

OH

O

H2N

AB

C

Br

OBn

NH2

Br

OBn

N SO2Ph1. PhSO2Cl/py

2. NaH, allyl bromide

- first synthesized by Boger et al. (1992)- cancer tissue pH ~6.2; normal tissue pH ~7.2

"...we have become interested in highly toxic compounds which can be detoxified by the formation of derivatives which may be cleaved at pH 6.2 with liberation of the toxin."

Zr

OBn

NSO2Ph

H3CCp Cp

OBn

NSO2Ph

ZrCp

Cp

-CH4

OBn

ZrCp

Cp N SO2PhI2

OBn

N SO2PhI

I

45%10% byproduct (can be recycled)

tBuLi,Cp2Zr(CH3)Cl

O

I

OBn

N SO2Ph6 steps

mech.?OMe

Me

N SMe

H Hcuracin A O

O

O O

Me HOH

(−)-prehalenaquinone

HNN

N

NHNH

N

NH

O

OO

O O

OO

MeMe

OHMe

NHHO

phakellistatin 3

MeNO

NH

OO

O OHMe

Me

Me

Me MeI

HO

doliculide

NNH

N

O

O

OHMe

MeOOH

H

H H

H

H

bioxalomycin α1

O

HO

Me

Me

MeHO Me

heliannuol BO O

O

OH

OO

O

Sch 49209


OBn

N SO2PhI

OAc

NAc OBn

N SO2Ph

OAc

OBn

N SO2Ph

OAc

N NAc

Me

Ac

Heck Rxn

a or b

a. Pd(OAc)2, NaOAc, NBu4Cl, DMFb. Pd(PPh3)4, NEt3, CH3CN

64%10%

30%70%

O

NSO2Ph

NH

Me

see Boger et al. JACS, 1988, 4796.

Pseudopterane 2,5-Furanocyclic Ring System324, Marshall

O

MeMe

O O

MeMe

HO

H H

HO

MeMe

HO

H H

H70:30

O

MeMe

HOH

H3 steps

O

MeMe

O

MnO2

O

MeMe

HOH

H

trans-isomer

cis-isomer

Core Ring System of the Cyathins885, Paquette

O

S

S O

S S120º C, cat. Et3N

OO

5 StepsKH18-cr-6;

NH4Cl,H2O

OH

MeMe

OO

O

Me Me

Aspicilin949, Sinha and Keinan

OO

O

O MeMe

MeMe

OO

O

O MeMe

MeMe

OMEMOH

OO

O

O MeMe

MeMe

OMEM

EtO2C

OO

Me

OAc

MeMe

OMEM

EtO2C

OHOH

OHO

OMe(+)-aspicilin

1. AD-mix-β

2. (CH3)2C(OMe)2

AD-mix-α

then3 steps

most reactive

equally reactive

AD-mix regioselectivity: Once A is dihydroxylated,B is much less reactive than C

CB

AA

A

A

"Stellatrienes"1027, Gleiter

2 steps

3 steps 3 steps

"In these cases, not only the possible interactions but also the beauty of the molecules1 initiated our studies."

1J. Aestetics Art Criticism 1990, 48, 191.

Examples:

"Key Reactions":

RO RO

hv

OR

baseO

CHR2

HO

RRIntramolecular Paterno-Büchi Base-induced cleavage

O

MeMe

O

OMe

OH

Kallolide A

O

MeMe

HO

Previous strategy:

OH

Me

S

SClMeO

OMe SHSH

HCl S

S HCl

MeLi

Synthesis of inverse demand Diels-Alder coupling partner:

OO

OH

MeMe

OO

OH

MeMe

via:

A B

BuLi

BuLi

HH

E (40%)Z (60%)


O

hv

O• [4+2]

O HO

OHO

DATMP

1. (COCl)2, DMSO2. Et3N

iPrLiMsCl,Et3N

name?

Angularly Fused Triquinanes 1396, Clive

RB

AX

B

AXR

OH

B

A R

H

B

R

H

A

General Scheme:

Co2(CO)8NaBH4,CeCl3 Bu3SnH

A or B = heteroatom; X = Br or SePh; R' = Me or H

O

Ph

H

O

Ph

OH

Ph

H

O

AcN

Ph

HOH O

Ph

OH

Me Me

OHOH

X

OH OHR'

no NaBH4/CeCl3;trans pdt observed

2-Azetines 1608, Marchand, Bott, and Archibald

OHHONH2

1. HOAc

2. HBr, HOAc3. KOH N

Et

N

Et

N2O4(various

conditions) NH2

Et ONO2

N

Et ONO2

N

Et ONO2

NO

NO2

N

Et ONO2

N

Et

NO

ClCO2Et

Ms2O

ClCO 2 Et

ClCO 2 Et

Tf2O

N

Et Cl

CO2Et

N

Et OMs

Ms

NTf

NTf

O

NTf

NOHO3 NH2OH

NMs

EtKOtBu

NMs not formed

NNO2

Et4 steps

Tetranitrotoluenes 1714, Nielson and Wilson

MeNO2

NO2O2NNO2

MeNO2

NO2NO2

MeNO2

NO2O2N

O2N O2N

MeNO2O2N

NO2

TNT

all slightly more dense than TNT due to presence of additional nitro group

MeNO2

NH2

O2N

MeNO2

NHNO2

O2N

MeNO2

NH2

O2N

1 2 3

HNO3

HOAc/Ac2OH

H2SO4H2S2O8

NO2

1

name?

MeNH2

NO2

O2N NO2

MeNO2O2N

NO2

O2NMe

N2

NO2

O2N NO2

O2NH3PO2

3 steps ONOSO3H

H2SO4

density (g/mL): 1.701 1.69 1.66 1.65

Me

favored by 12 kcal/mol


Sophoradiol2324, Johnson

F

TMS

F

TMS

HO

O

H

Me MgBr

MgBr2F

TMS

Br

F

TMS

CO2Et

F

TMS

CO2Et

Me

MeCO2Et

tBuOK

F

TMS

MeLi

TFA•

H

H

F

H

3 steps

"...first examples of nonenzymic, biomimetic polyene pentacyclizations..."

controls regiochem

controls D/E cis-syn configuration

terminates cyclization

H

H

H OH

SophoradiolHO

Strychnine2685, Rawal

N

O

O

H

HH

N

CN

NO2

5 steps

NH2

N CO2Me

N

N CO2Me

MeO2C CO2Me

MeO2C CHO

Me

then ClCO2Me, PhNEt2

N

N

HCO2Me

CO2Me

185 ºC

N

HN

H

CO2Me

O

TMS-I;

MeOH quench, ΔN

N

H

O

I

OTBS

I OTBSBr

N

O

HH

N

OH

isostrychnine strychnine

"ethanolic potash"

Rubrolone C Ring3453, Boger

O

Br Br

O

Br

O

Br O

O

Et3NO

O

CuCNLi22

O

O

O

DBU

O

OMe

Me

25 ºC, 15 minO

OO

OO

MeMe

HH

HH

exo transition state

O

O

OO

O

MeMe

H

H

O

O

O OHO

Me MeOH

1. NBS, H2O2. KOtBu

HO

O

OHHO

O

O

OHHO1. LiOH

2.NBS, Ph3P3. Zn, NH4Cl

MnO2

This space is intentionally left blank.

LDAK2CO3

1. Pd(OAc)2, Bu4NCl, K2CO32. HCl

MeHO Me


Cyclic Enol Ethers via Mo RCM4029, Grubbs

MoN Me

Ph

MeRORO

i-Pr i-Pr

R = CMe(CF3)2

OR1

O

OH HO OH

CO2Me

O

O

7 steps OO

O

Me

O

RO OR

R = CH2Ph

OO

O

Me

RO OR

Me

12 mol % [Mo] cat.

O

O

O

RO OR

O

O

O

HO OH

H2, Pd/C

CH3CHBr2,TiCl4, Zn,

TMEDA,cat. PbCl2

72%

n OR1n

R2

nOR1

General Scheme:

O nR1

O

O nR1

R2

OR1

n

Molybdenum Catalyst

R1 = H, Me; n = 1,2

Some Products:

Benzofuran NP Synthesis:

O

O O O

OPh

O Ph PhPh

Ph

Phn-Pr

Ph

Thiangazole4733, Heathcock

HN N

H

HN CO2MeCbz

O

OMe Me

Me

SBn

SBn

SBn

3 steps HN N

H

HN CO2H

O

OMe Me

Me

SBn

SBn

SBnO

Ph

Me

O

NHMe

OBn

H3NClHN N

H

HN

O

OMe Me

Me

SBn

SBn

SBnO

Ph NH

OMe

NHMe

O

OBn

N S

NHO

NS

N

SPh

MeHN

O

MeOH

Me

Me

Me

N S

NHO

NS

N

SPh

MeHN

O

MeO

Me

Me

Me

1. Na, NH32. NH4Cl3. TiCl2

N S

NS

N

SPh

Me

Me

MeO

N

Me

O

MeHN

N S

NS

N

SPh

Me

Me

MeO

N

Me

O

MeHN

DMP p-TsOH DDQ

Camptothecin5120, Comins

(−−n I)-thiangazole

N OMe

1. MesLi

2.

3. n-BuLi

N NMe

MeMe

CHO

N OMe

Li N

OLiMe

NMeMe

1. CeCl3

2.

3. H3O

CO2Me

O

Et

N OMe

OMeO2C

EtOH

N OMe

O

OEt

HO

NH

O

O

OEt

HO

(i-PrO)3Al

N Br

OH

N

O

O

OEtHO

N Br

N

O

O

OEtHO

N

Pd(OAc)2

(±)-camptothecin

1N HCl


Silphiperfol-6-ene and Methyl Cantabradienate5419, Snider

Me

CHO

Me

N Ot-Bu

O

t-Bu

CHO

Me

Me

MgBr1. PDC2. (COCl)2

Me

Me

OCl

DMAP, Et(i-Pr)2N

Me

Me•

O

[2+2]Me H

MeO

LiMe H

MeHO

Me H

Me

O

Mn(pic)3

MeLi

Me H

Me

HO Me

Na, NH3/EtOH

Me H

MeMe

Me

Me H

Me

TfO

KHMDS, PhN(Tf)2

Me H

Me

MeO2C

1. [Pd], CO

2. CH2N2

Grayanotoxin III5532, Matsuda and Shirahama

Me

OHTsO

MeO2C

Me

BnO6 steps

OTMS1. Δ,

2. 10% HF3. PDC MeO2C

Me

BnOH

H

O

4 stepsO

Me

O OH

H

O

Me

O O

H

HO Me

O

Me

O OH

H

O Me

SmI2

NaAuCl4•H2O

O

Me

O OH

H

Me

OH

OR

H

MeOR

SPh

10 steps1. n-BuLi

2. (PhS)2

O

MeMe

OMPM

ORMe

OR

SPhH

MeMe

MPMO

OHOR

MeOR

SPhH

MeMe

O

TBDMSO

H3 steps

ORMe

OR

H

MeMe

TBDMSO

OH

H

SmI2

ORMe

OR

H

MeMe

HO

O

HMe OR

R = MOM

7 steps

O H

ORMe

OR

SmI2

MeMe

HO

HOOH

MeHH OR

OHMe

OHMe

Me

HO

HOOH

MeHH OH

3 steps

silphiperfol-6-ene

methyl cantabradienate

(−)-grayanotoxin III

This space is intentionally left blank.


Illudin M6965, Kinder

Me

O ON2

MeMe

O

BrMe O

MeMeO

Br

O

Me OMeMe

Br

O

HOMe

MeMgBr KOH/MeOH

Me OMeMe

MeHO

OMeOH

Me OMeMe

MeHO

O

CrO3/H2SO4

Rh2(OAc)4

Me OHMeMe

MeHO

OH

LAHNBS

pyridine

Me OHMeMe

MeHO

O(±)-illudin M

Me OMeMe

MeHO

OH

LAH

Also, taxol.

JOC Year in Review: 1994 Baran Group Meeting Leah Simke · Forrest Gump Top 5 Most Cited ......

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