A catalytic deuteration of protected 3,4-dehydro-L-proline using RuCl2(PPh3)(3) followed by RuO4-oxidatian gave a 3,4-dideuterated L-pyroglutamic acid derivative which is considered to be a promising precursor far various deuterated amino acids. The present study demonstrates a stereoselective reduction of the amide carbonyl moiety leading to L-proline derivatives in which all of the ring methylenes are stereoselectively labeled with deuterium. (C) 1997 Elsevier Science Ltd.
Gold-Catalyzed Highly Enantioselective Synthesis of Axially Chiral Allenes
作者:Vanessa Kar-Yan Lo、Man-Kin Wong、Chi-Ming Che
DOI:10.1021/ol702970r
日期:2008.2.1
Axiallychiral allenes are synthesized from chiral propargylamines catalyzed by KAuCl4 in high yields (up to 93% yield) and excellent enantioselectivities (up to 97% ee) in CH3CN at 40 degrees C. The reaction has been applied to the synthesis of novel allene-modified artemisinin derivatives with the delicate endoperoxide moieties remaining intact. A tentative mechanism regarding gold(I)-catalyzed intramolecular
Stereodivergent Synthesis of (<i>2S</i>,<i>3S</i>,<i>4R</i>,<i>5R</i>)- and (<i>2S</i>,<i>3S</i>,<i>4R</i>,<i>5S</i>)-[3,4,5-D<sub>3</sub>]Proline Depending on the Substituent of the γ-Lactam Ring