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Synfacts 2005(0): 0031-0031  
DOI: 10.1055/s-2005-865379
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart · New York

A Stable P-Heterocyclic Carbene

Contributor(s): Victor Snieckus, Justin-Alexandre Morin
D. Martin, A. Baceiredo, H. Gornitzka, W. Schoeller, G. Bertrand*
University of California, Riverside, USA
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Publication History

Publication Date:
20 July 2005 (online)

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Significance

The preparation of the first stable P-heterocyclic carbenes (PHCs) is reported. A formal [3+2] cycloaddition of a diphosphaallylic cation, generated from the corresponding phosph­alkane with a dipolarophile leads to the PHCs in moderate yields. Crystallographic studies reveal that the phosphorus centers deviate only slightly from planarity, suggesting a possible increase in π-donating capability of the phosphorus atoms, thus increasing the ligand’s δ-donating ability. ­Carbonyl stretching frequencies for the cis-[RhCl(CO)2PHC] complex indicate that the metal center is a weaker π-donor compared to that in the analogous NHC complex.