抄録
The first total synthesis of novel antitumor antibiotic (+)-leinamycin (1) is reported. The unique structural features of leinamycin include the 1-oxo-1, 2-dithiolan-3-one moiety fused in a spiro fashion to an 18-membered lactam with an extensively conjugated thiazole ring. No other natural products with such an unusual dithiolanone moiety have been reported to date. The 18-membered lactam 19 was assembled efficiently from Seebach's dioxolanone 2 via sequential chemo- and stereoselective reactions including iterative application of our versatile thiol ester reductions. The delicate dithiolanone moiety of 1 was constructed stereoselectively by critical intramolecular delivery of a sulfur atom and the ensuing Beckmann fragmentation.
