Synthesis of the originally proposed structure of the styryl tetrahydropyranol-dihydropyranone natural product cryptoconcatone H from C2 -symmetric (±)-1,8-nonadiene-4,6-diol is reported. Desymmetrization by Mitsunobu reaction with crotonic acid established the requisite inter-ring stereochemical relationship and was followed by a highly diastereoselective Re2O7 catalyzed Prins cyclization with cinnamaldehyde to construct the 2,4,6-cis-tetrahydropyranol ring. Ring-closing metathesis resulted in formation of the dihydropyranone ring and completed of the synthesis in three steps and 32% overall yield. The brevity of the synthesis is the result of the recognition of hidden, inter-ring symmetry in the target and the ensuing choice of an appropriately symmetric diol as our starting material.

A general and convenient procedure for the synthesis of azinones is presented. Cyclopropylmethanol is readily introduced onto various azines where it functions as both a protecting group and surrogate for hydroxyl. After acidic deprotection, under mild reaction conditions, the corresponding azinones are formed and isolated in excellent yields. >20 examples are included along with a discussion of reaction optimization, scope, and mechanism.