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![Page 1: Planning a Reaction. Proposing a Procedure Library – Primary literature SciFinder Scholar – Secondary Literature Organic Syntheses Fieser Comprehensive.](https://reader030.fdocuments.net/reader030/viewer/2022032600/56649dce5503460f94ac1974/html5/thumbnails/1.jpg)
Planning a Reaction
![Page 2: Planning a Reaction. Proposing a Procedure Library – Primary literature SciFinder Scholar – Secondary Literature Organic Syntheses Fieser Comprehensive.](https://reader030.fdocuments.net/reader030/viewer/2022032600/56649dce5503460f94ac1974/html5/thumbnails/2.jpg)
Proposing a Procedure
• Library– Primary literature• SciFinder Scholar
– Secondary Literature• Organic Syntheses• Fieser• Comprehensive Organic Transformations
COOH
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Case Study: Benzoic Acid
• Literature: Try a Grignard Reaction• Well defined purpose• Propose a reaction
COOHBr1. Mg
2. CO2
3. H3O+
Done with the hard part—Right????
![Page 4: Planning a Reaction. Proposing a Procedure Library – Primary literature SciFinder Scholar – Secondary Literature Organic Syntheses Fieser Comprehensive.](https://reader030.fdocuments.net/reader030/viewer/2022032600/56649dce5503460f94ac1974/html5/thumbnails/4.jpg)
Considerations
• More left to consider than you think!– Scale of reaction– Solvent/amount of solvent– Glassware• Size• Inert atmosphere?
– Order of reagents and addition– Temperature and reaction time– Isolation/purification of product
![Page 5: Planning a Reaction. Proposing a Procedure Library – Primary literature SciFinder Scholar – Secondary Literature Organic Syntheses Fieser Comprehensive.](https://reader030.fdocuments.net/reader030/viewer/2022032600/56649dce5503460f94ac1974/html5/thumbnails/5.jpg)
Scale of Reaction
• Macroscale: multigram• Miniscale: 0.5g-10g• Microscale: <0.5g• Consider– Purpose– Further steps– Practicalities– Projected yield
• Apply to multistep synthesis
![Page 6: Planning a Reaction. Proposing a Procedure Library – Primary literature SciFinder Scholar – Secondary Literature Organic Syntheses Fieser Comprehensive.](https://reader030.fdocuments.net/reader030/viewer/2022032600/56649dce5503460f94ac1974/html5/thumbnails/6.jpg)
Solvent• What solvent?– Solubility, protic/aprotic
• How much solvent?– Scale down: use proportionally more solvent– Scale up: use proportionally less solvent– Rule of thumb: 0.1M-0.5M
• Example: You are basing your reaction on a procedure that has 5 mmol of bromobenzene in 10 mL of ether solvent. If you are scaling down to 0.5 mmol starting material, how much ether should you use?
![Page 7: Planning a Reaction. Proposing a Procedure Library – Primary literature SciFinder Scholar – Secondary Literature Organic Syntheses Fieser Comprehensive.](https://reader030.fdocuments.net/reader030/viewer/2022032600/56649dce5503460f94ac1974/html5/thumbnails/7.jpg)
Glassware
• Size?– 1/2 to 1/3 full
• Heating/cooling?• Anhydrous?• Adding reagents?
![Page 8: Planning a Reaction. Proposing a Procedure Library – Primary literature SciFinder Scholar – Secondary Literature Organic Syntheses Fieser Comprehensive.](https://reader030.fdocuments.net/reader030/viewer/2022032600/56649dce5503460f94ac1974/html5/thumbnails/8.jpg)
• Which reagent first? How do we add gradually? Does it matter if we switch the addition funnel and reflux condenser?
![Page 9: Planning a Reaction. Proposing a Procedure Library – Primary literature SciFinder Scholar – Secondary Literature Organic Syntheses Fieser Comprehensive.](https://reader030.fdocuments.net/reader030/viewer/2022032600/56649dce5503460f94ac1974/html5/thumbnails/9.jpg)
cotton and CaCl2
septum
stirbar
Heating:Waterbath?Sandbath?Hotplate?
Cooling:Icebath?How long?
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Reaction Isolation and Purification
• How would you determine reaction times if not given?
• Propose a workup. – Must consider solvent and other impurities, scale
• Propose a purification.– Must consider characteristics of impurities
![Page 11: Planning a Reaction. Proposing a Procedure Library – Primary literature SciFinder Scholar – Secondary Literature Organic Syntheses Fieser Comprehensive.](https://reader030.fdocuments.net/reader030/viewer/2022032600/56649dce5503460f94ac1974/html5/thumbnails/11.jpg)
Multistep Reaction
• Ideal multistep reaction is to make a valuable product from cheap commodity chemicals in high yield and purity, maintaining green chemistry principles
O
CH2(CO2H)2,pyr, heat
O
OH
Br2acetic acid
O
OHBr
Br
stereoisomer?
Br
K2CO3water or acetone