917617-58-4Relevant academic research and scientific papers
Stereospecific diphosphination of activated acetylenes: A general route to backbone-functionalized, chelating 1,2-diphosphinoethenes
Dodds, Deborah L.,Haddow, Mairi F.,Orpen, A. Guy,Pringle, Paul G.,Woodward, Gary
, p. 5937 - 5945 (2006)
The symmetrical diphosphanes R2P-PR2 {where R = Ph (1a), Cy (1b), or But (1c)} are made by the reaction of R 2PLi with R2PCl. The unsymmetrical diphosphanes R 2P-PR′2 {where R = But and R′ = Ph (2a); R = But and R′ = o-Tol (2b); R′ = Cy and R′ = Ph (2c); R = Cy and R′ = o-Tol (2d); R = Cy and R′ = But (2e)} are made by the reaction of R2P(BH3)Li with R′2PCl followed by deprotection with Et2NH. Diphosphanes 1a,b and 2a-d react with ZC≡CZ (Z = CO2Me) to give the corresponding R2-PCZ=CZPR2 (3a,b) or R 2PCZ=CZPR′2 (4a-d). The reaction of 2a,b with HC≡CZ give the corresponding R2PCH=CZPR2 (5a,b). A mechanism is proposed that accounts for the cis stereospecificity and the regioselectivity of these diphosphinations. Treatment of [PtCl 2(1,5-cod)] or [PdCl2(NCPh)2] with a selection of the diphosphines (3-5) gave the expected chelate complexes, four of which, [PtCl2(3b)], [PtCl2(4a)], [PtCl2(4c)], and (PdCl2(4a)], have had their crystal structures determined.
