[3,3]sigmatropic ring expansion of cyclic thionocarbonates. 13.1 synthesis of medium-membered heterocyclic allenes and synthetic application to antifungal constitutent of Sapium japonicum
thionocarbonates (2i-k) afforded a new type of strained 8-membered heterocyclic allenes (3i-k) in high yields. The MNDO optimized structure of 3i indicated the allenyl moiety was bent and strained. The reactivity of 8-membered cyclic allenes was also examined. Further, using this methodology with a novel application of a SmI2-HMPA reduction of the resulting heterocyclic allene (3n), an antifungal constituent
Synthesis of medium-membered heterocyclic allenes by [3,3]sigmatropic rearrangement and its synthetic application to the antifungal constituent of sapium japonicum
Medium-membered heterocyclic allenes were synthesized by the [3,3]sigmatropic rearrangement of cyclic thionocarbonates. Using this methodology and a novel application of a SmI2-HMPA reduction, an antifungal constituent of Sapium japonicum, methyl 8-hydroxy-5,6-octadienoate, was synthesized.