Sterically hindered diphosphines (Ph2P)2CCHR (R = Me or Ph) and their derivatives
摘要:
Reactions of (Ph2P)2C=CHR (R = Me or Ph) with E (E = S or Se) yielded the corresponding mono- and di-chalcogenides and the mixed S/Se derivatives, H-1, C-13 and P-31 NMR parameters for which are reported. These are rationalized in terms of conformational preferences associated with the relative P-E and phosphorus-lone pair orientations. The complexes [M(CO)4{(PhP)2C=CHR}] (M = Mo or W, R = Me or Ph) have also been prepared and have NMR parameters which can be accounted for similarly. The crystal structure of (Ph2P)2C=CHMe has been determined by single-crystal X-ray diffraction and shows that the solid-state conformation is similar to that deduced in solution on the foregoing basis.
esters by strong Lewis acids via the formation of covalent adducts is a classic strategy to give reactivity; however, this approach frequently incurs limited turnover due to the low efficiency in the dissociation of catalyst from a stable catalyst-product complex. While the use of some weak interaction catalysts that can easily dissociate from any bonding complexes in the reaction system would solve this
Reactivity of carbanions stabilized by two alpha phosphorus groups
作者:Mudlagiri B. Goli、Samuel O. Grim
DOI:10.1016/s0040-4039(00)79752-8
日期:1991.7
The stabilized anion [Ph2P(S)]2CH}− with lithium as counter cation 1a reacts with formaldehyde or benzaldehyde to give vinylidene phosphine sulfides [Ph2P(S)]2CCHR, where R is H or Ph, respectively (3, 4). The same anion with potassium as counter cation 1b gives vinyl phosphine sulfides (9−11). The formation of these two different classes of compounds is dependent on the the cation and the solvent
Sterically hindered diphosphines (Ph<sub>2</sub>P)<sub>2</sub>CCHR (R = Me or Ph) and their derivatives
作者:Jonathan L. Bookham、Fosca Conti、H. Christina E. McFarlane、William McFlane、Mark Thornton-Pett
DOI:10.1039/dt9940001791
日期:——
Reactions of (Ph2P)2C=CHR (R = Me or Ph) with E (E = S or Se) yielded the corresponding mono- and di-chalcogenides and the mixed S/Se derivatives, H-1, C-13 and P-31 NMR parameters for which are reported. These are rationalized in terms of conformational preferences associated with the relative P-E and phosphorus-lone pair orientations. The complexes [M(CO)4(PhP)2C=CHR}] (M = Mo or W, R = Me or Ph) have also been prepared and have NMR parameters which can be accounted for similarly. The crystal structure of (Ph2P)2C=CHMe has been determined by single-crystal X-ray diffraction and shows that the solid-state conformation is similar to that deduced in solution on the foregoing basis.