已开发出一种简单有效的方法,使用支持的试剂系统CuBr 2 / Al 2 O 3 -Na 2 CO 3 / Al 2 O 3在一个锅中由β-酮酸酯和二酮合成α-溴酸酯和酮,其中β-酮酸酯首先与CuBr 2 / Al 2 O 3反应,产物α-溴-β-酮酸酯与Na 2 CO 3 / Al 2 O 3反应以高产率得到最终产物α-溴酸酯。
The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed
Four new cyclopropane-based bisoxazolines were synthesized and applied to cobalt-catalyzed cross-coupling reactions between racemic alpha-bromo esters and aryl Grignard reagents. The reaction afforded a series of chiral alpha-arylalkanoic esters with high yields and good enantioselectivities (up to 93% yield, 92:8 er). This research focuses on the cross-coupling between racemic alpha-bromopropanoate and p-isobutylphenyl Grignard reagent's which provides ibuprofen ester efficiently. Furthermore, ibuprofen ester 7e was transformed into (S) -ibuprofen (99:1 er) via hydrolysis and recrystallization. (C) 2016 Elsevier Ltd. All rights reserved.
Efficient .alpha.-halogenation of acyl chlorides by N-bromosuccinimide, N-chlorosuccinimide, and molecular iodine
作者:David N. Harpp、L. Q. Bao、Catherine J. Black、John G. Gleason、Roger A. Smith
DOI:10.1021/jo00911a026
日期:1975.11
One-pot synthesis of α-bromoesters and ketones from β-ketoesters and diketones using supported reagents system
作者:Tadashi Aoyama、Toshio Takido、Mitsuo Kodomari
DOI:10.1016/j.tetlet.2004.01.014
日期:2004.2
A simple and efficient method has been developed for the synthesis of α-bromoesters and ketonesfrom β-ketoesters and diketones in one pot using a supported reagents system, CuBr2/Al2O3–Na2CO3/Al2O3, in which β-ketoester reacts first with CuBr2/Al2O3 and the product, α-bromo-β-ketoester, reacts with Na2CO3/Al2O3 to give the final product, α-bromoesters in good yields.
已开发出一种简单有效的方法,使用支持的试剂系统CuBr 2 / Al 2 O 3 -Na 2 CO 3 / Al 2 O 3在一个锅中由β-酮酸酯和二酮合成α-溴酸酯和酮,其中β-酮酸酯首先与CuBr 2 / Al 2 O 3反应,产物α-溴-β-酮酸酯与Na 2 CO 3 / Al 2 O 3反应以高产率得到最终产物α-溴酸酯。
<i>o</i>-Nitrophenyl Sulfoxides: Efficient Precursors for the Mild Preparation of Alkenes
作者:Xiao Lu、Timothy E. Long
DOI:10.1021/jo902248z
日期:2010.1.1
to be efficient synthetic precursors of various alkene types. The elimination occurs in toluene and NaOAc to generate substituted and terminal alkenes. Alkene products were easily obtained in high purity due to the simultaneous precipitation of the o-nitrophenyl sulfenic acid byproduct. The methods described have practical applications for the preparation of unsaturated compounds under mild, thermolytic