Stereoselective acylation of the E,E-vinylketene silyl N,O-acetal and its application to the synthesis of khafrefungin.
Stereoselective acylation of the E,E-vinylketene silyl N,O-acetal possessing a chiral auxiliary has been achieved by using acid anhydrides and SnCl4. Acid anhydrides having alkyl chains gave the adducts in excellent stereoselectivity. The formal synthesis of khafrefungin has been accomplished by the methodology.