Phosphinidenes and Related Intermediates. III. Reactions of Phosphinylidenes and Phosphinothioylidenes with Conjugated Dienes

Abstract

Phenylphosphonic and phenylphosphonothioic dichlorides were dechlorinated with magnesium to generate phenylphosphinylidene and phenylphosphinothioylidene, respectively, in the presence of several 1,3-dienes. Reactions of phenylphosphinothioylidene with 2,3-dimethylbutadiene and 1,3-cyclohexadiene gave Diels-Alder type reaction products, that is, 3,6-dihydro-1,2-thiaphosphorin derivatives (5 and 6) and 6-phenyl-5,6-thiaphosphabicyclo[2.2.2]oct-2-ene 6-sulfide (14), respectively. Reaction of 2,3-diphenylbutadiene with phenylphosphinothioylidene afforded 1,2,4,5-tetraphenyl-1,2,3,6-tetrahydro-1,2-diphosphorin 1,2-disulfide (10), whereas that with phenylphosphinylidene gave 1,3,4-triphenyl-3-phospholene 1-oxide (12). The differences of these reactions have been discussed.