Philip Kisanga

P(RNCH2CH2)3N: AN EFFICIENT PROMOTER FOR THE SYNTHESIS OF 3-SUBSTITUTED COUMARINS

ABSTRACT The title compounds wherein R = Me or i-Pr function as efficient promoters for the formation of coumarins in good to excellent yields (80–95%) from salicylaldehydes and di-activated methylene compounds of the type R′CH2CO2Et (R′ = CO2Et, COMe, CN). Although the yields are not generally superior to those reported in the literature, our methodology is more convenient in that milder conditions and shorter reaction times are facilitated by the use of the aforementioned commercially available catalysts.

P(RNCH2CH2)3N-catalyzed diastereoselective synthesis of oxazolines

Abstract We report herein that the strong nonionic bases P(RNCH 2 CH 2 ) 3 N(R=Me, 1a ; i -Pr, 1b ) catalyze the diastereoselective synthesis of thirteen oxazolines in the presence of 5–30% of these catalysts. The formation of the oxazolines proceeds under very mild conditions in good to excellent yields with high diastereoselectivity (>95:5) for the trans isomer.

P(i-PrNCH2CH2)3N: An efficient nonionic catalyst for the regioselective Michael addition of a β,γ-unsaturated ester and a nitrile

Abstract Michael additions of a β,γ-unsaturated ester and a nitrile to a variety of α,β-unsaturated ketones can be effected with high regioselectivity and in good yields using P(i-PrNCH2CH2)3N as a catalyst.

P(RNCH2CH2)3N: Superbasic and Catalytic Cages

In contrast to acyclic P(NR2)3, the title pro-azaphosphatrane cages (first reported from our laboratories) are exceedingly strong nonionic bases that protonate to give the extraordinarily weak acids HP(RNCH2CH2)3N+ (pKa in MeCN, ∼41). Thus we have found that commercially available P(MeNCH2CH2)3N is a superior nonionic base for the synthesis of porphyrins, alkenes, C-monoalkylation of esters and β-hydroxy nitriles. We have also discovered that P(RNCH2CH2)3N cages function as superior catalysts for the synthesis of β-hydroxy nitriles, α,β-unsaturated nitriles and silyl-protected alcohols. Protective acylations of alcohols are very efficiently promoted by P(MeNCH2CH2)3N.