ABSTRACT
The secondary RP-(-)-menthyl alkylphosphine oxide was confirmed as configurationally stable toward base and was used in base-promoted alkylation, stereospecifically affording P-retained bis or functional tertiary phosphine oxides in excellent yields. The alkylated products were deoxygenated using oxalyl chloride followed by ZnCl2-NaBH4 to form P-inversed bidentate phosphine boranes in high stereoselectivities.
ABSTRACT
Functionalized P,C-stereogenic tertiary phosphine oxides were prepared by the addition of (RP)-menthyl phenylphosphine oxide to activated olefins, in high drP and drC, and were isolated in excellent yields. The reaction was readily catalyzed by Ca(OH)2 or occurred with gentle heating. A wide range of substrates, including vinyl ketones, esters, nitriles, and nitro alkenes, can be used in the reaction.
ABSTRACT
P,C-Stereogenic α-amino phosphine oxides were prepared from the addition of (RP )-menthyl phenyl phosphine oxide to chiral aldimines under neat condition at 80 °C in up to 91:9 drC and 99% yields. The diastereoselectivity was mainly induced by chiral phosphorus that showed matched or mismatched induction with (S)- or (R)-aldimines, respectively.
Subject(s)
Imines/chemistry , Organophosphorus Compounds/chemistry , Catalysis , Molecular Structure , StereoisomerismABSTRACT
P,C-stereogenic 1,3-bisphosphinylpropanes 3 that have up to five stereogenic centers could be obtained stereoselectively in high yields by a one-step reaction of (RP)-menthylphenylphosphine oxide 1 with α,ß-unsaturated aldehydes 2 catalyzed by KOH at room temperature. A mechanism was proposed as to involve a stereoselective intermolecular 1,3'-phosphorus migration from the 1,2-adduct of 1 with 2 to another 2 generating a 1,4-adduct that subsequently reacts with 1 to produce 3.