LITHIUM AMINO ALKOXIDE-EVANS ENOLATE MIXED AGGREGATES: ALDOL ADDITION WITH MATCHED AND MISMATCHED STEREOCONTROL
Building on structural and mechanistic studies of lithiated enolates derived from acylated oxazolidinones (Evans enolates) and chiral lithiated amino alkoxides, we have found that amino alkoxides amplify the enantioselectivity of aldol additions. Pairing enantiomeric series afford matched and mismatched stereoselectivities. The structures of mixed tetramers showing 2:2 and 3:1 (alkoxide-rich) stoichiometries are determined spectroscopically. Rate and computational studies provide a viable mechanistic and stereochemical model based on direct reaction of the 3:1 mixed tetramers and unanswered questions for the 2:2 mixed aggregates.
Aldol Addition; Chiral Alkoxides; Lithuim enolates; Mixed Aggregates; Chemistry
Collum, David B.
Coates, Geoffrey; Fors, Brett P.
Chemistry and Chemical Biology
Ph. D., Chemistry and Chemical Biology
Doctor of Philosophy
dissertation or thesis