Unusual Ring-Closure Reactions During the Oxidation of 1,1′-Bi(3-methylphosphol-2-ene) with Hexafluoroacetone — Formation of a Tricyclic Fluorine-Containing Phosphorane

✍ Scribed by Vollbrecht, Sebastian ;Vollbrecht, Alexander ;Jeske, Jörg ;Jones, Peter G. ;Schmutzler, Reinhard ;Du Mont, Wolf-Walther

• Publisher: Wiley (John Wiley & Sons)
• Year: 1997
• Tongue: English
• Weight: 426 KB
• Volume: 130
• Category: Article
• ISSN: 0009-2940
• DOI: 10.1002/cber.19971300623

✦ Synopsis

Abstract

Reduction of the isoprene—PCl~3~ adduct 1 with magnesium powder, or with Si~2~Cl~6~, furnished P‐chloro‐3‐methyl‐phosphol‐2‐ene, 2, in satisfactory yield. Further reduction of 2 with Si~2~Cl~6~ gave the new trichlorosilyl‐3‐methylphosphol‐2‐ene, 3. The reaction of 2 with magnesium powder, with 3, or with 1/2 equivalent of Si~2~Cl~6~ provided the new γ^3^P‐γP‐diphosphane 1,1′‐bi(3‐methylphosphol‐2‐ene) 4. Reduction of 4 with Si~2~Cl~6~ led to 3. Oxidation of 4 with selenium gave the 1,2‐diphosphane diselenide, 5. The oxidation of 4 with hexafluoroacetone led to a mixture of products, from which a novel tricyclic phosphorane 6 was separated. the structure of 196 was determined by X‐ray diffraction; the coordination geometry at phosphorus in distorted trigonal bipyramidal, with a very long equatorial P—C(CF~3~)~2~ bond of 193.2(2) pm.