Synthesis of enantiomerically pure α-amino-β-hydroxy-cyclobutanone derivatives and their transformations into polyfunctional three-and five-membered ring …
Ketenes readily cycloadded to (R)-tert-butyldihydrooxazole to yield enantiomerically pure bicyclic cyclobutanones. The cycloadditions proceeded with unusual regiochemistry giving predominantly or exclusively protected α-amino-β-hydroxycyclobutanone derivatives. The adducts could be converted into a variety of interesting enantiopure intermediates equipped with many functional groups: α-amino-β-hydroxy cyclopropane carboxylic acid derivatives, ...
[Krafft, Marie E.; Bonaga, Llorente V. R.; Felts, Andrew S.; Hirosawa, Chitaru; Kerrigan, Sean Journal of Organic Chemistry, 2003 , vol. 68, # 15 p. 6039 - 6042]