Asymmetric Total Synthesis of (+)-Inthomycin C via O-Directed Free Radical Alkyne Hydrostannation with Ph₃SnH and Catalytic Et₃B: Reinstatement of the Zeeck–Taylor (3<i>R</i>)-Structure for (+)-Inthomycin C

Abstract

A new pathway to (+)-inthomycin C is reported that exploits an O-directed free radical hydrostannation reaction on (-)-12 and a Stille cross-coupling as key steps. Significantly, the latter process was effected on 19 where a gauche-pentane repulsive interaction could interfere. Our stereochemical studies on the alkynol (-)-12 and the enyne (+)-7 confirm that Ryu and Hatakeyama's (3S)-stereochemical revision of (+)-inthomycin C is invalid and that Zeeck and Taylor's original (3R)-stereostructure for (+)-inthomycin C is correct.