Diphosphiranes 3a-3f are obtained by action of diazo derivatives and carbenes on the trans-diphosphene 1. The structures are elucidated by spectroscopic methods. In all cases the cycloaddition reaction is stereoselective.
The cyclopropanation of 1 using sonochemical generation of methylene or halogeno-carbenes constitutes an interesting alternative in the diphosphirane synthesis. Furthermore, ultrasonic effects in a chlorinated solvent allow the first substitution of a diphosphirane without ring-opening.
Addition of dihalocarbenes to a diphosphene gave diphosphiranes which undergo rearrangement on treatment with alkyllithium reagents to afford 1,3-diphospha-allene; dynamic NMR studies on the allene are described.
The reaction of saturated and unsaturated organomagnesium compounds with the monohalogenated diphosphiranes, 1a-b, and their isomers, the 1,3-diphosphapropenes, 2a-b, leads to a series of substituted 1,3-diphosphapropenes and 1,3-diphosphadienes 4-8 (a-b), but with the dihalogeno-derivatives 1c-d and 2c-d, it gives quantitative yields of 1,3-diphospha-allene 9. The reaction occurs via an anionic ring-opening