SYNTHETIC STUDIES TOWARD ENETRIYNE NATURAL PRODUCTS & EXAMINATION OF THE SYNTHETIC SCOPE AND MECHANISM OF DMDS ADDITION TO 1,4-ENYNES
A general, convenient route to enetriyne natural products, exemplified by several Fistulina hepatica metabolites, has been developed. The method is advantageous for the synthesis of conjugated polyynes as compared to traditional methods. The synthetic scheme is highlighted by the coupling of a triyne and alkenyl halide segment by a modified Stille reaction. Three enetriynes were synthesized for comparison with natural products isolated from F. hepatica shake cultures. The scope and utility of the reaction between DMDS and 1,4-enynes was explored. Successful syntheses of a number of 1,4-enynes were realized in good yield, however, varied yields were obtained for DMDS derivatization of the 1,4-enynes. A tether of less than five methylene groups between distal functional groups and the enyne appears to significantly diminish the formation of 2,5-disubstituted thiophenes. Possible pathways for the mechanism of the reaction were investigated. Current evidence suggests the mechanism for the reaction between DMDS and 1,4-enyne may proceed through either an enyne-MeSI adduct or allene intermediate.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:polyacetylenes fritsch buttenberg wiechell rearrangement 1 4 enynes thiophenes dimethyl disulfide
Date of Publication:01/01/2003