Synthesis and Structure of a 1‐Phospha‐2‐boraacenaphthene Derivative and Its Chalcogenation Reactions

Abstract

The first stable 1‐phospha‐2‐boraacenaphthene 1 was synthesized by the reduction of 1‐dimesitylboryl‐8‐dichlorophosphinonaphthalene (2 a) with elemental magnesium, and it was fully characterized. The chalcogenation reaction of 1 with elemental sulfur or selenium afforded the unique heterocycles, 2‐thia‐ and 2‐selena‐1‐phospha‐3‐boraphenalenes 9 S and 9 Se, respectively, through the insertion of the chalcogen atom into a PB bond of 1. Further chalcogenation of 9 afforded the corresponding phosphine chalcogenides. These newly obtained chalcogenated compounds have been characterized. The unique dynamic behavior of 2‐chalcogena‐1‐phospha‐3‐boraphenalene‐1‐chalcogenides 10 in solution has also been described.