Asymmetric Tandem Conjugate Addition-Aldol Condensation withN-Acryloyloxazolidines Derived from 2-Phenylglycinol

Abstract The tandem 1,4‐addition–aldol condensation reaction of diethylzinc, α,β‐unsaturated chiral enantiopure oxazolidines derived from 2‐phenylglycinol, and carbonyl compounds is disclosed. The reaction proceeds through a radical‐polar crossover mechanism involving the aldol condensation of a trisubstituted zinc enolate through a Zimmerman–Traxler transition state. Installation of a 2‐pyridine moiety at the hemiaminal position of the chiral auxiliary allows obtaining both excellent asymmetric induction and diastereoselectivity (up to >90 % de ). The developed protocol is suitable for aromatic and aliphatic aldehydes, as well as ketones.