Stereoselective Hydride Reductions of Cyclic N-Diphenylphosphinyl Imines. Highly Diastereoselective Syntheses of Protected Primary Amines
摘要:
Reduction of N-diphenylphosphinyl imines of variously substituted cyclohexanones, cyclopentanones, and bicyclic ketones with lithium tri-sec-butylborohydride provides highly diastereoselective procedures for the syntheses of N-diphenylphosphinyl amines which represent protected primary amines that can be unmasked by mild acidic cleavage. Attack of cyclohexyl derivatives occurs almost exclusively via equatorial approach to yield axial amine derivatives while cyclopentyl and bicyclic imines are attacked from the less sterically encumbered faces.
Stereoselective Hydride Reductions of Cyclic N-Diphenylphosphinyl Imines. Highly Diastereoselective Syntheses of Protected Primary Amines
作者:Robert O. Hutchins、Jeffrey Adams、Melvin C. Rutledge
DOI:10.1021/jo00128a009
日期:1995.11
Reduction of N-diphenylphosphinyl imines of variously substituted cyclohexanones, cyclopentanones, and bicyclic ketones with lithium tri-sec-butylborohydride provides highly diastereoselective procedures for the syntheses of N-diphenylphosphinyl amines which represent protected primary amines that can be unmasked by mild acidic cleavage. Attack of cyclohexyl derivatives occurs almost exclusively via equatorial approach to yield axial amine derivatives while cyclopentyl and bicyclic imines are attacked from the less sterically encumbered faces.
Mercury-Catalyzed Rearrangement of Ketoximes into Amides and Lactams in Acetonitrile
作者:Chennan Ramalingan、Yong-Tae Park
DOI:10.1021/jo070297k
日期:2007.6.1
An acetonitrile solution of mercury(II) chloride has been found to catalyze efficiently the conversion of a diverse range of ketoximes into their corresponding amides/lactams.
An Efficient and Versatile One-Pot Beckmann Rearrangement of Ketoximes Using Mesitylenesulfonyl Chloride
作者:Yong-Tae Park、Chennan Ramalingan
DOI:10.1055/s-2008-1042948
日期:2008.5
acyclic ketoximes in the presence of lithium hydroxide in tetrahydrofuran, efficiently rearrange into their corresponding lactams and amides. The stereo-chemistry of diazepan-5-one lactams resulting from the rearrangement of heterocyclic ketoximes (piperidin-4-one oximes), has been deduced based on one- and two-dimensional NMR analyses. The seven-membered heterocyclic ring of the product lactams adopts chair