New phosphine oxide aziridinyl phosphonates as chiral Lewis bases for the Abramov-type phosphonylation of aldehydes

A series of Lewis bases were screened for Abramov-type phosphine additions to aldehydes. A novel phosphine oxide aziridinyl phosphonate POAP-A was found to be better than the others in forming the product in 96% yield and with 42% ee. The absolute configuration of the newly synthesized POAP Lewis bases was determined by single-crystal X-ray analysis.

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(R)-2-((R)-2-(Diethoxyphosphoryl)aziridin-1-yl)butyl 4-methylbenzenesulfonateC17H28NO6PS[α]D25=-12.5 (c 0.5, CH2Cl2)Source of chirality: asymmetric synthesisAbsolute configuration: (R,R)

(R)-2-((S)-2-(Diethoxyphosphoryl)aziridin-1-yl)butyl 4-methylbenzenesulfonateC17H28NO6PS[α]D25=+44 (c 2.4, CH2Cl2)Source of chirality: asymmetric synthesisAbsolute configuration: (R,S)

Diethyl ((S)-1-((R)-1-(diphenylphosphoryl)butan-2-yl)aziridin-2-yl)phosphonateC22H31NO4P2[α]D25=+6.0(c 1.0, CH2Cl2)Source of chirality: asymmetric synthesis, X-ray analysisAbsolute configuration: (S,R)

Diethyl ((R)-1-((R)-1-(diphenylphosphoryl)butan-2-yl)aziridin-2-yl)phosphonateC22H31NO4P2[α]D25=-8.2(c 0.3, CH2Cl2)Source of chirality: asymmetric synthesisAbsolute configuration: (R,R)