Asymmetric Alkylation and Aldol Reactions of D-Mannitol-Derived Chiral Oxazolidin-2-one Derivatives

摘要

In the preceeding article,we have introduced a new chiral oxazolidin-2-one auxiliary(1)derived from a cheap D-mannitol,and demonstrated the chiral selectivity in alkylation,aldol reaction and beta-lactam synthesis.The present work began with a search for useful chiral directing groups with which to control the chiral selectivity.Because the rigidity of cyclic structures contributes significantly to control of chirality,the l,2:5,6-di-O-cyclohexylidene-D-mannitol(2)was used for the synthesis of oxazolidin-2-one chiral auxiliary(3)comparing the selectivity with the auxiliary(1)in alkylation and aldol reactions.