Phenylsilane reduction of phosphine oxides with complete stereospecificity

Marsi, Kenneth L.

doi:10.1021/jo00916a041

Cited by 143 publications

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“…The frontside mode of hydride delivery means that the relative stereochemistry of the three phosphorus substituents does not change, provided that pseudorotation in the phosphorane A is slow. Marsi 15,16 proposed a similar fourcentered hydride-transfer mechanism for the stereoretentive reductions of phosphine oxides by PhSiH 3 .…”

Section: ■ Backgroundmentioning

confidence: 99%

Theoretical Investigation of the Mechanisms and Stereoselectivities of Reductions of Acyclic Phosphine Oxides and Sulfides by Chlorosilanes

Krenske

2012

J. Org. Chem.

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Computational studies were performed to explain the highly varied stereoselectivities obtained in the reductions of acyclic phosphine oxides and sulfides by different chlorosilanes. The reductions of phosphine oxides by HSiCl(3), HSiCl(3)/Et(3)N, and Si(2)Cl(6) and the reductions of phosphine sulfides by Si(2)Cl(6) (all in benzene) were explored by means of B3LYP, B3LYP-D, and SCS-MP2 calculations. For the reductions of phosphine oxides by HSiCl(3), the calculations support the mechanism proposed by Horner in which a hydride is transferred from silicon to phosphorus through a four-centered, frontside transition state. This mechanism leads to retention of stereochemistry at phosphorus. For the other three reductions, two classes of mechanisms were explored. Phosphorane-based mechanisms that were previously proposed by Mislow and involve SiCl(3)(-) were compared with novel alternative mechanisms that involve nonionic rearrangement processes. In one of these, donor-stabilized SiCl(2) is formed as an intermediate. The calculations support a phosphorane-based mechanism for the reductions of phosphine oxides by HSiCl(3)/Et(3)N and Si(2)Cl(6) (which proceed with inversion) but favor the rearrangement pathways for the reductions of phosphine sulfides by Si(2)Cl(6) (which proceed with retention).

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Section: ■ Backgroundmentioning

confidence: 99%

Theoretical Investigation of the Mechanisms and Stereoselectivities of Reductions of Acyclic Phosphine Oxides and Sulfides by Chlorosilanes

Krenske

2012

J. Org. Chem.

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“…Reduction to phosphine could be achieved with the mild reducing agent phenylsilane, which has been used successfully in the past to reduce P-chirogenic groups whilst retaining the optical integrity of the compound [10]. In a test study, neat phenylsilane slowly reduced a diastereomeric mixture of the oxides to the phosphines 10a and b, over 3 days at 80°C.…”

Section: Resultsmentioning

confidence: 99%

P-chirogenic phosphines. MOP/diPAMP hybrids, their oxide crystal structures, reduction studies and alternative syntheses

Higham

Clarke

Müller‐Bunz

et al. 2005

Journal of Organometallic Chemistry

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“…[5,6] Reduction of 6 with phenylsilane [7] and radical-based reduction of 7 with tris(trimethylsilyl)silane [8] gave 1-phenyl-1,3a,4,5,6,6a-hexahydrocyclopenta[b]phosphole (4) quantitatively and with complete retention of configuration at P (Scheme 1). [5,7,8] Scheme 1. Synthesis of racemic 1-phenyl-1,3a,4,5,6,6a-hexahydrocyclopenta [b]phosphole (4) Separation of 4 into its enantiomers was achieved by an oxidative resolution route, [9] as shown in Scheme 2.…”

Section: Resultsmentioning

confidence: 99%

New Monodentate P,C‐Stereogenic Bicyclic Phosphanes: 1‐Phenyl‐1,3a,4,5,6,6a‐hexahydrocyclopenta[b]phosphole and 1‐Phenyloctahydrocyclopenta[b]phosphole

et al. 2004

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Racemic 1-phenyl-1,3a,4,5,6,6a-hexahydrocyclopenta[b]-phosphole (4) was separated into enantiomerically pure 1-phenyl-1,3a,4,5,6,6a-hexahydrocyclopenta[b]phosphole 1-oxides [(R P )-6 and (S P )-6] by an oxidative resolution procedure involving treatment of 4 with menthyl bromoacetate, crystallization of the resulting diastereoisomeric phosphonium bromides 8, and stereoselective hydrolysis of the diastereomerically pure salts to the corresponding enantiomerically pure phosphane oxides. Stereoretentive reduction of P=O in

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Phenylsilane reduction of phosphine oxides with complete stereospecificity

Cited by 143 publications

References 0 publications

Theoretical Investigation of the Mechanisms and Stereoselectivities of Reductions of Acyclic Phosphine Oxides and Sulfides by Chlorosilanes

Theoretical Investigation of the Mechanisms and Stereoselectivities of Reductions of Acyclic Phosphine Oxides and Sulfides by Chlorosilanes

P-chirogenic phosphines. MOP/diPAMP hybrids, their oxide crystal structures, reduction studies and alternative syntheses

New Monodentate P,C‐Stereogenic Bicyclic Phosphanes: 1‐Phenyl‐1,3a,4,5,6,6a‐hexahydrocyclopenta[b]phosphole and 1‐Phenyloctahydrocyclopenta[b]phosphole

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