β-アルコキシビニルスルホンとアルデヒドのSmI2による環化反応の開発

抄録

Marine polycyclic ethers have attracted the attention of synthetic organic chemists by the complex structures and potent bioactivities. We now report a useful method for the construction of cyclic ether based on SmI₂-induced reductive cyclization. Reaction of (E)- and (Z)-beta-alkoxyvinyl sulfones having an aldehyde with SmI₂ in the presence of MeOH in THF stereoselectively gave 2,6-syn-5,6-trans- and 2,6-syn-2,3-cis-tetrahydropyrans, respectively, which have a sulfonylmethyl group as the side chain. Transformation of the sulfonylmethyl group to a methyl group was performed by reduction with Raney-Ni in refluxing EtOH. The present method was successfully applied to the synthesis of the KLMN-ring system of gymnocin-A, a marine polycyclic ether.

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