[4+2] Versus [2+2] Cycloadditions in the Sphere of P-Heterocycles as Useful Synthetic Tools

Author(s): Gyorgy Keglevich

Journal Name: Current Organic Chemistry

Volume 6 , Issue 10 , 2002

Become EABM
Become Reviewer


The Diels-Alder reaction of 1,2-dihydrophosphinine oxides with dienophiles, such as dimethyl acetylenedicarboxylate (DM AD) and maleic acid derivatives affords phosphabicyclo [2. 2.2] oct adien es or bicyclooctenes, respectively, that are precursors of low-coordinated P-fragments, methylenephosphine oxides useful in the phosphorylation of alcohols, phenols and amines. An alternative mechanism involving an intermediate with a pentavalent, pentacoordinated phosphorus atom was also substantiated and proved. Reaction of the P-2, 4, 6-trialkylphenyl dihydrophosphinine oxides with DMAD followed an unexpected protocol to give the corresponding stabilised phosphonium ylides. The intermediates are oxaphosphetes formed by the [2+2] cycloaddition of the P=O group of the P-cycle and the triple bond of DMAD. This kind of reaction, that is the consequence of the presence of the electronreleasing trialkylphenyl group, has never been observed earlier and proved to be general to take place with a variety of cyclic phosphine oxides.

Keywords: Cycloadditions, P-Heterocycles, 1,2-dihydrophosphinine oxides, acetylenedicarboxylate, methylenephosphine, oxaphosphetes, pentacoordinated phosphorus

open access plus

Rights & PermissionsPrintExport Cite as

Article Details

Year: 2002
Page: [891 - 912]
Pages: 22
DOI: 10.2174/1385272023373833

Article Metrics

PDF: 15