The Wittig Reaction : 30 Years Later

Abstract

New and old ylid reactions are described and their mechanisms examined.     

Oxidative Chlorination of Acetanilides with Hydrogen Chloride/m-Chloroperbenzoic Acid/N,N-Dimethylformamide System

The reaction of acetanilides with relevant amounts of HCI and m-chloroperbenzoic acid in DMF at room temperature gave the desired chloro-substituted acetanilides in good yields.     

Synthesis of novel axially chiral cyclic benzopolysulfides

Novel axially chiral benzopentathiepins were synthesized by sulfurization of dithiastannole. Naphthyl moiety was introduced near the pentathiepin ring by Suzuki-Miyaura cross-coupling reaction. Pentathiepins were found as diastereomeric mixture. Rotational energy barrier for C-C bond was estimated by theoretical calculation. Energy barrier for the inversion of pentathiepin ring was experimentally determined by variable temperature ¹H NMR.     

Accelerated phosphodiester cleavage of bis( p -nitrophenyl)-phosphate by receptors

Phosphodiester cleavage of BNPP can be accelerated by various degradative receptors including enzymes. In the hydrolytic cleavage of BNPP, a bell-shaped receptor concentration-rate profile composed of a positive-catalysis phase at low receptor concentrations and a negative-catalysis phase at excess receptor concentration was observed. The negative catalysis can be explained by nonproductive binding, leading to an increase of the activation energy barrier and a decrease of the reaction rate.