Significant counterion effect of the In(III)–pybox complex in highly enantioselective carbonyl-ene reactions of ethyl glyoxylate
摘要:
A highly efficient enantioselective carbonyl-ene reaction of ethyl glyoxylate catalyzed by an In(III)-pybox complex, which is designed based on the counterion effect, is reported. Reactions of both aliphatic and aromatic 1,1-disubstituted olefins proceed smoothly to give enantioenriched homoallylic alcohols with excellent yields and enantioselectivities. In addition, electron-withdrawing as well as donating groups on the phenyl ring of alpha-methyl styrenes are tolerated in this reaction. (C) 2010 Elsevier Ltd. All rights reserved.
Enantioselective Carbonyl–Ene Reactions Catalyzed by Chiral Cationic Dirhodium(II,III) Carboxamidates
作者:Xichen Xu、Xiaochen Wang、Yuxiao Liu、Michael P. Doyle
DOI:10.1021/jo5013674
日期:2014.12.19
An enantioselectivecarbonyl–enereaction of glyoxylate esters with 1,1-disubstituted alkenes catalyzed by chiral cationic dirhodium(II,III) carboxamidates is described. The paddlewheel dirhodium(II,III) carboxamidates having one open coordination site at each rhodium smoothly catalyze the carbonyl–enereaction to afford homoallylic alcohol products in good isolated yields with high enantioselectivities
Highly Enantioselective Carbonyl-ene Reactions Catalyzed by a Hindered Silyl−Salen−Cobalt Complex
作者:Gerri E. Hutson、Apurva H. Dave、Viresh H. Rawal
DOI:10.1021/ol071342d
日期:2007.9.1
enantioselective carbonyl-enereactions of various 1,1-disubstituted and trisubstituted alkenes with ethyl glyoxylate. The reactions are catalyzed by a new Co-salen complex, in which bulky triisobutylsilyl (TIBS) substituents occupy the positions ortho to the phenolic oxygens. This complex catalyzes the reactions under nearly ideal conditions - at room temperature and using catalyst loadings as low
<i>C</i><sub>2</sub>-Symmetric Copper(II) Complexes as Chiral Lewis Acids. Enantioselective Catalysis of the Glyoxylate−Ene Reaction
作者:David A. Evans、Christopher S. Burgey、Nick A. Paras、Tomas Vojkovsky、Steven W. Tregay
DOI:10.1021/ja980549m
日期:1998.6.1
ene reaction with glyoxylate esters;3 however, due to the limiting reactivity of the catalyst-glyoxylate complex,4 only nucleophilic 1,1-disubstituted olefins may be employed. We have recently reported that bidentate bis(oxazolinyl) (box) Cu(II) complexes 1-3 are effective enantioselective catalysts in Diels-Alder5 and aldol reactions6 with substrates that can participate in catalyst chelation. In this
A highlyenantioselective carbonyl-ene reactioncatalyzed by In(III)−pybox is described. Both 1,1-disubstituted alkenes and 1,1,2-trisubstituted alkenes proceeded smoothly to give the ene products in high yields up to 97% and with excellent diastereoselectivity and enantioselectivities up to >99:1 and 99%, respectively.
Multikilogram Synthesis of a Hepatoselective Glucokinase Activator
作者:Joshua R. Dunetz、Martin A. Berliner、Yanqiao Xiang、Timothy L. Houck、Fabrice H. Salingue、Wang Chao、Chen Yuandong、Wang Shenghua、Yun Huang、Douglas Farrand、Steven J. Boucher、David B. Damon、Teresa W. Makowski、Mark T. Barrila、Raymond Chen、Isamir Martínez
DOI:10.1021/op300194c
日期:2012.10.19
This work describes the process development and manufacture of early-stage clinical supplies of a hepatoselective glucokinase activator, a potential therapy for type 2 diabetes mellitus. Critical issues centered on challenges associated with the synthesis of intermediates and API bearing a particularly racemization-prone a-aryl carboxylate functionality. In particular, a T3P-mediated amidation process was optimized for the coupling of a racemization-prone acid substrate and a relatively non-nucleophilic amine. Furthermore, an unusually hydrolytically-labile amide in the API also complicated the synthesis and isolation of drug substance. The evolution of the process over multiple campaigns is presented, resulting in the preparation of over 110 kg of glucokinase activator.