A highly efficient and straightforward stereoselective synthesis of novel chiral α-acetylenic ketones

Abstract

A very efficient and straightforward synthesis of novel chiral α-acetylenic ketones of type 3 has been developed. Starting from commercially available l-(−)-serine 4, and through the Garner's aldehyde 5, ethynyloxazolidine 2 was formed in good overall yield. Condensation of the corresponding lithium acetylide 7 with different aliphatic and aromatic aldehydes 5 and 8a– h at low temperatures yielded the respective propargylic alcohols 9a– i. Subsequent mild oxidation of 9a– i with 10-I-4-iodinane oxide (IBX) 12 afforded chiral α-acetylenic ketones 3a– i almost quantitatively.