REAGENT-CONTROLLED ENANTIOSELECTIVE HOMOALDOL REACTION WITH CHIRAL 1-OXYALLYLLITHIUM DERIVATIVES. ENANTIO-DIVERGENT TUNING BY ACHIRAL TITANIUM REAGENTS

Article abstract of DOI:10.1016/S0040-4039(00)95614-4

Optically active 2-alkenyl carbamates are deprotonated by n-butyllithium with retention of configuration.Lithium titanium exchange by Ti(OiPr)4 proceeds with retention and by ClTi(NEt2)3 with inversion of configuration.The stereochemical course of addition to aldehydes is mainly determined by the chiral center of the metal allyl reagents to offer a flexible route to both enantiomers of highly substituted ketones.