U. Matteoli, Valentina Beghetto, Cristina Schiavon
May 8, 1997
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0
Influential Citations
15
Citations
Journal
Tetrahedron-asymmetry
Abstract
Abstract A new synthesis of CHIRAPHOS starting from readily available 2,3-bis(diphenylphosphinyl)-1,3-butadiene has been devised. The key step of the synthesis is the hydrogenation of the diene to rac -2,3-bis(diphenylphosphinyl)butane. This reduction can be conveniently performed by treating 2,3-bis(diphenylphosphinyl)-1,3-butadiene with NaBH 4 in THF/CH 2 Cl 2 mixtures. The racemic diphosphine oxides are subsequently resolved using (2 S ,3 S )-(+)- and (2 R ,3 R )-(−)-2,3- O -dibenzoyltartaric acid [(+)- and (−)-DBTA]. Reduction of the resolved phosphine oxides is carried out using trichlorosilane.