Selective formation of a C3-symmetric P-stereogenic tris(phosphine) via platinum-catalyzed asymmetric alkylation of a tris(secondary phosphine). Issue 24 (31st December 2015)

• Record Type: Journal Article
• Authors: Xu, Zhiming; Cain, Matthew F.; Rupert, Alexander V.; Glueck, David S.; Golen, James A.; Rheingold, Arnold L.
• Is Part Of: Tetrahedron, asymmetry. Volume 26:Issue 24(2015)
• Page Start: 1459
• Page End: 1468
• Publication Date: 2015-12-31
• Subjects: Asymmetry (Chemistry) -- Periodicals; 547.005
• DOI: 10.1016/j.tetasy.2015.11.002
• Languages: English
• ISSNs: 0957-4166

Abstract

Graphical abstract: Abstract: Alkylation of MeC(CH2 PHPh)3 1 with 2-cyanobenzyl bromide and NaOSiMe3 using the catalyst precursor Pt(( R, R )-Me-DuPhos)(Ph)(Cl) gave a mixture of tris(phosphines) enriched in C 3 -MeC(CH2 PPh(CH2 ( o- C6 H4 CN))3 3 ; Cu-catalyzed phosphination yielded C 1 -enriched3 . Oxidation of3 by sulfur or H2 O2 formed MeC(CH2 P(E)Ph(CH2 ( o -C6 H4 CN))3 (E = S4 ; E = O5 ). Repeated recrystallization gave a low yield of ( R, R, R )-4, which was crystallographically characterized. Tris(phosphine)3 was formed with a diastereomeric ratio (dr = C 3 / C 1 ) of 2.1(2) and enantiomeric ratios of 54(10) and 3.8(7) for C 3 -3 and C 1 -3 respectively, which showed that the selectivity of the triple alkylation was not the same at each site (substrate control).