PROCEDIMENTO STEREOSPECIFICO PER PREPARARE AZETIDINONI

摘要

Chiral azetidinones II (R1 optionally substituted phenyl, R2 = C1-C4 alkyl or aryl, R3 = H or an N-protecting group) are prepared by reacting compound III (R4 = carboxy protecting group) with an organometallic derivative and treating the resultant dianion with a compound IV. The azetidinones II are stereospecifically prepared by the above process and may be converted to azetidinones VIII (R5 = hydroxy protecting group), useful in the preparation of penems.