A facile synthesis of (4S)-4-[(1R)-1-carboxyethyl]-1-(tert-butyldimethylsilyl)azetidin-2-one : A key intermediate of 1-β-methylcarbapenems

Article abstract of DOI:10.1055/s-1997-1502

Titanium enolate-mediated aldol-type reaction of the chiral N-propionyl-1,3-benzoxazinone 4 with 4-acetoxyazetidin-2-one (5) gave the 2-(2-oxoazetidin-4-yl)propionic acid derivative 6 in high yield with high selectivity, which was transformed into (4S)-4-[(1R)-1-carboxyethyl]-1-(tert-butyldimethylsilyl)azetidin-2-one (3), a key intermediate of 1-β-methylcarbapenems 1.