Meyer-Schuster Rearrangement of .gamma.-Sulfur-Substituted Propargyl Alcohols: A Convenient Synthesis of .alpha.,.beta.-Unsaturated Thioesters
摘要:
gamma-Sulfur-substituted propargyl alcohols 1a-e and 1ij reacted with polyphosphoric acid trimethylsilyl ester (PPSE) to give the alpha,beta-unsaturated thioesters 3a-e and 3ij in good yields. However, the reactions of 3,3-dibutyl-1 -(phenylthio)propargyl alcohol (1k) and 1-(phenylthio)ethynyl- 1-cyclo alkanols 1l-n with PPSE gave the enyne sulfides 2k-n exclusively.
Electroinitiated oxygenation of alkenyl sulfides and alkynes in the presence of thiophenol
作者:Junichi Yoshida、Shogo Nakatani、Sachihiko Isoe
DOI:10.1021/jo00070a021
日期:1993.8
Electrolysis of alkenyl sulfides in the presence of thiophenol with bubbling of molecular oxygen gave the corresponding alpha-(phenylthio) carbonyl compounds with the consumption of a catalytic amount of electricity. An electroinitiated radical chain mechanism has been proposed. The reaction also took place without electrochemical initiation, but much (5-50 times) longer reaction time was required for the completion of the reaction. The potential utility of the present reaction in organic synthesis is demonstrated by the net 1,2-transposition of a phenylthio group and a carbonyl group. The electroinitiated oxygenation of ketene dithioacetals also proceeded smoothly to give the corresponding alpha-(phenylthio) thiol esters. It was also found that the electroinitiated oxygenation of alkynes in the presence of thiophenol gave alpha-(phenylthio) carbonyl compounds. A mechanism involving the initial formation of alkenyl sulfides has been proposed.
Multiplexing of Combinatorial Chemistry in Antimycin Biosynthesis: Expansion of Molecular Diversity and Utility
Diversity‐oriented biosynthesis of a library of antimycin‐like compounds (380 altogether) was accomplished by using multiplex combinatorial biosynthesis. The core strategy depends on the use of combinatorial chemistry at different biosynthetic stages. This approach is applicable for the diversification of polyketides, nonribosomal peptides, and the hybrids that share a similar biosynthetic logic.
gamma-Sulfur-substituted propargyl alcohols 1a-e and 1ij reacted with polyphosphoric acid trimethylsilyl ester (PPSE) to give the alpha,beta-unsaturated thioesters 3a-e and 3ij in good yields. However, the reactions of 3,3-dibutyl-1 -(phenylthio)propargyl alcohol (1k) and 1-(phenylthio)ethynyl- 1-cyclo alkanols 1l-n with PPSE gave the enyne sulfides 2k-n exclusively.