描述了基于在硫原子上被芳基或烷基自由基的分子内均质取代(S H i)合成环状亚磺酸酯和亚磺酰胺的通用且有效的方法。烷基和苯并稠合的化合物都可以直接从容易制备的无环前体中获得。对映体富集的硫基杂环是通过S H i过程形成的,硫原子上的构型反转。前手性自由基的环化进行的立体化学结果各不相同,具体取决于传入自由基的大小。2-吡啶基和2-喹啉基会生成联芳基化合物,这是由于攻击芳基亚磺酸盐的邻位而不是亲硫取代引起的。
dialkoxycarbonylation of various aromatic and aliphatic alkynes affording a wide range of 1,4-dicarboxylic acid diesters in high yields and selectivities. Kinetic studies suggest the generation of 1,4-dicarboxylic acid diesters via cascade hydroesterification of the corresponding alkynes. Based on these investigations, the chemo- and regioselectivities of alkyne carbonylations can be controlled as shown by switching
The challenging room temperature Pd-catalyzed methoxycarbonylation for a wide array of alkynes with excellent branched selectivity has been developed.
已开发出具有出色支链选择性的广泛烯烃室温Pd催化的甲氧羰基化反应。
Metal‐Free Directed C−H Borylation of Pyrroles
作者:Zheng‐Jun Wang、Xiangyang Chen、Lei Wu、Jonathan J. Wong、Yong Liang、Yue Zhao、Kendall N. Houk、Zhuangzhi Shi
DOI:10.1002/anie.202016573
日期:2021.4.6
conspicuously underdeveloped. Here, we develop a general strategy for the site‐selective C−Hborylation of pyrroles by using only BBr3 directed by pivaloyl groups, avoiding the use of any metal. The site‐selectivity is generally dominated by chelation and electronic effects, thus forming diverse C2‐borylated pyrroles against the steric effect. The formed products can readily engage in downstream transformations
Application of chiral ligands: carbohydrates, nucleoside-lanthanides and other Lewis acid complexes to control regio- and stereoselectivity of the dipolar cycloaddition reactions of nitrile oxides and esters
作者:Mirosław Gucma、W. Marek Gołębiewski、Maria Krawczyk
DOI:10.1039/c4ra15975f
日期:——
and (Z)-pent-2-en-1-yl esters were examined. Excellent enantioselectivities with moderate to good regioselectivities were achieved for crotonates with complexes of BiBr3 with (+)-(4,6-benzylidene)methyl-α-D-glucopyranoside C, with the L-ascorbic acid I–FeCl3 system, and with lipase Candida antarctica. High enantiomeric excess was observed for isopropyl ester and benzyl ester. The outstanding ee values
Pyrrolidine modulators of chemokine receptor activity
申请人:Merck & Co., Inc.
公开号:US06372764B1
公开(公告)日:2002-04-16
The present invention is directed to pyrrolidine compounds of the formula I:
(wherein R1, R2, R3, R4c, R4d, and R4f are defined herein) which are useful as modulators of chemokine receptor activity. In particular, these compounds are useful as modulators of the chemokine receptors CCR-3 and/or CCR-5.