Organocatalytic asymmetric conjugate addition of t-butyl nitroacetate to o-quinone methides: synthesis of optically active alpha-nitro-beta, beta-diaryl-propionates

An asymmetric conjugate addition of t-butyl nitroacetate to in situ generated o-quinone methides had been developed. A chiral squamide derived from 9-amino-9-deoxyepiquinine was found to be the efficient catalyst. alpha-Nitro-beta, beta-diaryl-propionates could be obtained in good yields and with excellent enantioselectivities.