- Synthesis, resolution, and application of 2,2′-bis(diphenylphosphino) -3,3′-binaphtho[b]furan (BINAPFu)
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(±)-2,2′-Bis(diphenylphosphino)-3,3′-binaphtho[2,1-b] furan (BINAPFu) was synthesized from 2-naphthoxyacetic acid in a five-step sequence in 62% overall yield. A variety of reported resolution procedures for biaryl bisphosphines did not work with (±)-BINAPFu; thus, a new resolution method was developed, involving the Staudinger reaction of the aforementioned racemate of BINAPFu with an enantiopure camphor sulfonyl azide derivative. The resulting diastereomeric phosphinimines were separated by flash chromatography. Subsequent hydrolysis to the corresponding bis-phosphine oxide and trichlorosilane reduction provided enantiopure BINAPFu. The absolute stereochemical configuration of BINAPFu was established by X-ray crystallography. BINAPFu was compared with commercially available 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene (BINAP) in Pd(0)-catalyzed intermolecular Heck reactions. Investigation of the Heck arylation of 2,3-dihydrofuran showed BINAPFu to be more efficacious than BINAP in dioxane at 30°C. A variety of phosphorus selenides were prepared, and the 1JP-Se coupling constants measured, to obtain a comparative scale of parent phosphine basicity. The phosphorus atoms in BINAPFu were found to be electron deficient when compared with BINAP but slightly more electron rich than trifurylphosphine.
- Andersen, Nell G.,Parvez, Masood,McDonald, Robert,Keay, Brian A.
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p. 145 - 161
(2007/10/03)
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- A simple resolution procedure using the Staudinger reaction for the preparation of P-stereogenic phosphine oxides
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The resolution of a variety of (±)-P-stereogenic phosphines is achieved by exploiting the Staudinger reaction of a (±)-phosphine with enantiopure (1S,2R)-O-(tert-butyldimethylsilyl)isobornyl-10-sulfonyl azide. The resulting mixtures of diastereomeric phosphinimines are generally separable by fractional crystallization or flash chromatography. Subsequent acid-catalyzed hydrolysis provides the corresponding optically pure phosphine oxides in high yields.
- Andersen,Ramsden,Che,Parvez,Keay
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p. 7478 - 7486
(2007/10/03)
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- Synthesis, resolution, and applications of 2,2′-bis(diphenylphosphino)-3,3′-binaphtho[2,1-d]furan
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A short five-step synthesis of (±)-2,2′-bis(diphenylphosphino)-3,3′-binaphtho[2,1-b]furan (BINAPFu, 1) starting from 2-naphthoxyacetic acid is reported. The resolution of BINAPFu 1 was possible using our newly developed resolution procedure for phosphines
- Andersen, Neil G.,Parvez, Masood,Keay, Brian A.
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p. 2817 - 2820
(2007/10/03)
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