Organocatalysis in sustainable solvent media

Question 1

What are the key challenges for organocatalysis in aqueous media?

Answer 1

Solubility of organic compounds, hydrolytic instability of compounds and intermediates, reduced propensity for intermolecular interactions

Question 2

What are the key benefits of reaction in aqueous media?

Answer 2

Excellent economic and environmental credentials, biocompatibility, organocatalysts generally stable in presence of water, inorganic salts and bases have excellent solubility

Question 3

How do we evaluate green credentials of a process?

Answer 3

12 principles of green chemistry, life cycle analyses of solvents with resource depletion, air emissions and energy considered along with environmental health and safety considerations

Question 4

What are key features of homobenzoin reaction in water?

Answer 4

Reaction yield improved by long alkyl chains, suggesting micelle formation. Mild bases able to be used. Excellent yields except ortho-substituted. Moderate TONs attributed to partial decomposition of NHC over time.

Question 5

How can saturated brine solutions impact reactivity?

Answer 5

If mechanism improved by micelle formation, poorer reactions seen in brine as disrupted by presence of salt.
Improvement in brine, potentially via use of water as proton shuttle. Increase in ionic strength by brine addition.

Question 6

How can organocatalysis and biocatalysis be combined to give benefits?

Answer 6

Use of cofactor mimics and enzymes to enable greener, more stereoselective, broader substrate scope co-factor biocataysis.