Enantioselective Desymmetrization of Glutarimides Catalyzed by Oxazaborolidines Derived from cis-1-Amino-indan-2-ol
摘要:
Enantioselective reductive desymmetrization of glutarimides,has been achieved employing an oxazaborolidine catalyst derived from cis-1-amino-indan-2-ol. The reaction was found to proceed through a stereoablative process, that upgraded the enantioselectivity of an intermediate,hydroxy-lactam. The reaction: was generally tolerant of a number of substituents in the 4-position giving enantiomeric excesses of greater than 82%.
β-Deuterium Isotope Effects on Amine Basicity, “Inductive” and Stereochemical
作者:Charles L. Perrin、Brian K. Ohta、Joshua Kuperman
DOI:10.1021/ja038343v
日期:2003.12.1
Secondary beta deuterium isotope effects on acidity constants of ammonium ions are measured using a remarkably precise NMR titration method. Deuteration is found to increase the basicity of methylamine, dimethylamine, benzylamine, and N,N-dimethylaniline. The effect is attributed to a lowered zero-point energy of a CH bond adjacent to an amine nitrogen. The method permits a determination of the stereochemical
Stereochemistry of β-Deuterium Isotope Effects on Amine Basicity
作者:Charles L. Perrin、Brian K. Ohta、Joshua Kuperman、Jordan Liberman、Máté Erdélyi
DOI:10.1021/ja0511927
日期:2005.7.1
Secondary β-deuterium isotope effects on aminebasicities are measured using a remarkably precise NMR titration method. Deuteration is found to increase the basicity of methylamine, dimethylamine, benzylamine, N,N-dimethylaniline, 2-methyl-2-azanorbornane, and pyrrolizidine. The increase in dimethylamine arises entirely from enthalpy, contrary to a previous report. The method permits a determination
Application of the chiral base desymmetrisation of imides to the synthesis of the alkaloid jamtine and the antidepressant paroxetine
作者:Christopher D Gill、Daniel A Greenhalgh、Nigel S Simpkins
DOI:10.1016/j.tet.2003.08.046
日期:2003.11
The synthesis of the alkaloid jamtine and the antidepressant paroxetine have been addressed by a strategy involving asymmetric desymmetrisation of prochiral imides by a chiral lithium amide base. A short reaction sequence, starting with a cyclohexane fused succinimide, led to the structures originally reported for the alkaloid jamine and its derived N-oxide. The structures synthesised are shown not to correspond with those originally reported. A second sequence involves desymmetrisation of a 4-arylglutarimide, and provides a short enantioselective synthesis of the drug substance paroxetine. (C) 2003 Elsevier Ltd. All rights reserved.