Functionalized proline with double hydrogen bonding potential: highly enantioselective Michael addition of carbonyl compounds to β-nitrostyrenes in brine
synthetic manipulation of S-proline allows access to prolinamides 5–7 as organocatalysts capable of double hydrogen bonding for enantioselectiveMichaeladdition reactions of carbonyl compounds to β-nitrostyrenes. It is shown that prolinamide catalyst 7 leads to addition products with a high diastereo- as well as enantioselectivity. The transition state structure involving the binding of electrophilic