LIGAND COUPLING THROUGH HYPERVALENT INTERMEDIATES. REACTION OF HETEROARYL SULFOXIDES WITH ORGANOMETALLICS REAGENTS AND THEIR IMPLICATIONS

Abstract

Abstract Earlier, pentacoordinate phosphorus and sulfur compounds were presumed to be of 3sp3d hybridization.1 However, a three-centered-four-electron bond, called a hypervalent bond by Musher,2 was suggested by Rundle and others3 to be consistent with p-orbitals in the early 1950s. The structure of one such compound, SF4, is shown below. Although the original theoretical treatment of hypervalent structure using three sp2- and a p-orbital was modified slightly by introduction of 3d orbitals into the calculation,4,5 the structural feature of such hypervalent compounds has remained the same. Following two stable sulfuranes, one by Kapovits et al. 6 and another by Martin and his coworkers7, are the first organic σ-sulfuranes which have both two polar and longer S[sbnd]O bonds nearly at 180°. Hypervalent interaction was noticed in the extremely short distance between the neutral divalent sulfenyl sulfur atom and the weakly nucleophilic oxygen atom of nitro group of the following compounds, we prepared for X-ray crystallographic analyses. Thus the hypervalent bonding is considered to be quite common and readily formed.