Facile and Effective Copper-Mediated Cyclization Reaction of Cyclopropylideneacetic Acids (or Esters) and Cyclopropylideneacetonitriles
摘要:
The full details of the copper-mediated cyclization reaction of cyclopropylideneacetic acids (or esters) and cyclopropylidenenitriles, the synthetic application of this reaction, and the study of the reaction mechanism are reported.
Diastereoselective Diels−Alder Reactions of a Novel Cyclopropenyl-Containing Chiral Auxiliary
摘要:
A novel cyclopropenyl-containing 1,3-spiroaminoalcohol auxiliary has been used in a variety of asymmetric Diels-Alder reactions providing endo adducts with diastereomeric ratios ranging from 2:1 up to >99:1. In addition, unexpected regiochemistry was observed for a Diels-Alder reaction between cyclopropenyl dienophile and 4-vinyl-1,2-dihydronapthalene.
It has been established that a cationic rhodium(I)/H8–BINAP complex catalyzes the asymmetric [2 + 2 + 2] cycloaddition of 1,6-enynes with cyclopropylideneacetamides to produce spirocyclohexenes in excellent enantioselectivity with retaining cyclopropane rings.
现已确定,阳离子铑(I)/ H 8 -BINAP配合物可催化1,6-炔烃与环亚丙基乙酰胺的不对称[2 + 2 + 2]环加成反应,生成具有优异对映选择性并保留环丙烷环的螺环己烯。
[4 + 2] Cycloaddition of thiophene S-monoxides to activated methylenecyclopropanes
作者:Thies Thiemann、Daisuke Ohira、Yuanqiang Li、Tsuyoshi Sawada、Shuntaro Mataka、Karsten Rauch、Mathias Noltemeyer、Armin de Meijere
DOI:10.1039/b003850o
日期:——
determined as being endo,syn. The Wittig olefination of cyclopropanone hemiacetal to generate the methylenecyclopropanes and the subsequent cycloaddition can be carried out in a one-pot operation. This procedure is one of many potential one-pot or multi-component reactions involving stabilized phosphoranes. A further example of this type of reaction is shown in the novel desilylation–Wittig olefination
It has been established that a cationicrhodium(I)/H8‐binapcomplex catalyzes the [3+2+2] cycloaddition of 1,6‐diynes with cyclopropylideneacetamides to produce cycloheptadiene derivatives through cleavage of cyclopropane rings. In contrast, a cationicrhodium(I)/(S)‐binapcomplex catalyzes the enantioselective [2+2+2] cycloaddition of terminal alkynes, acetylenedicarboxylates, and cyclopropylideneacetamides
Asymmetric Diels−Alder Reactions of Chiral Cyclopropylidene Imide Dienophiles: Preparation of <i>gem</i>-Dimethyl- and Spirocyclopropane Norbornyl Carboxylic Acids
作者:Jeffrey T. Kuethe、Dalian Zhao、Guy R. Humphrey、Michel Journet、Arlene E. McKeown
DOI:10.1021/jo052516c
日期:2006.3.1
A highly efficient strategy has been developed for the rapid asymmetric synthesis of gem-dimethyl and spirocyclopropyl norbornyl carboxylicacids. The key transformation involved the unprecedented asymmetricDiels−Alderreaction of highly reactive β,β-cyclopropyl-α,β-unstaturated N-acyloxazolidinones with cyclopentadiene affording the adducts in high yield and de.
Chromanol derivatives—A novel class of CETP inhibitors
作者:Alexandros Vakalopoulos、Carsten Schmeck、Michael Thutewohl、Volkhart Li、Hilmar Bischoff、Klemens Lustig、Olaf Weber、Holger Paulsen、Harry Elias
DOI:10.1016/j.bmcl.2010.10.110
日期:2011.1
Based on our former development candidate BAY 38-1315, optimization efforts led to the discovery of a novel chemical class of orally active cholesteryl ester transfer protein (CETP) inhibitors. The chromanol derivative 19b is a highly potent CETP inhibitor with favorable pharmacokinetic properties suitable for clinical studies. Chemical process optimization furnished a robust synthesis for a kilogram-scale process. (C) 2010 Elsevier Ltd. All rights reserved.