New isoxazolidine-based chiral auxiliaries for asymmetric syntheses

Article abstract of DOI:10.1016/S0040-4039(97)00580-7

New chiral auxiliaries based on the bicyclic-isoxazolidine skeleton, 3-oxa-2,7-diazabicylo[3,3,0]octane derivatives, were synthesized in 60-80% overall yields from amino acids. Asymmetric alkylation and boron aldol reaction using the auxiliaries proceeded with high selectivities. 'Carboxylic amide' has been used for the asymmetric boron-mediated aldol reaction for the first time.