Synthesis of oxygen heterocycles via alkynyltungsten compounds*
نویسنده
چکیده
This short review article covers some useful applications of alkynyltungsten compounds to the syntheses of complex lactones. Two types of cyclizations will be emphasized: (1) cycloalkenylation of tungsten-alkynol compounds with aldehydes to give α-alkylidene oxacarbeniums, further leading to α-alkylidene lactones and (2) intramolecular [3+2]-cycloaddition of epoxides to give bicyclic lactones. The new methodologies can provide a short synthesis of enantiopure lactones such as (–)-epilitsenolide C2, (+)-listenolide C1, (+)-isodihydromahubanolide A, (+)-blastmycinone, and (–)-epi-blastmycinone.
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