Preparation of chiral organochalcogeno-α-methylbenzyl alcohols via biocatalysis. The role of Daucus carota root
摘要:
A series of organochalcogeno acetophenones 3 has been submitted to the action of enzymes from Daucus carota root. Some of the chalcogeno ketones tested afforded the chiral organochalcogeno-alpha-methylbenzyl alcohols 4 in excellent enantiomeric excesses (>99%), under mild and environmentally friendly conditions. The stereoselectivity of the reduction is in accordance with Prelog's rule. Enzymatic kinetic resolution as alternative process was used to obtain the chiral ortho-organochalcogeno-alpha-methylbenzyl alcohols in excellent enantiomeric excess (>99%). (C) 2003 Elsevier Ltd. All rights reserved.
Preparation of chiral organochalcogeno-α-methylbenzyl alcohols via biocatalysis. The role of Daucus carota root
摘要:
A series of organochalcogeno acetophenones 3 has been submitted to the action of enzymes from Daucus carota root. Some of the chalcogeno ketones tested afforded the chiral organochalcogeno-alpha-methylbenzyl alcohols 4 in excellent enantiomeric excesses (>99%), under mild and environmentally friendly conditions. The stereoselectivity of the reduction is in accordance with Prelog's rule. Enzymatic kinetic resolution as alternative process was used to obtain the chiral ortho-organochalcogeno-alpha-methylbenzyl alcohols in excellent enantiomeric excess (>99%). (C) 2003 Elsevier Ltd. All rights reserved.
Microwave-assisted reaction of aryl diazonium fluoroborate and diaryl dichalcogenides in dimethyl carbonate: a general procedure for the synthesis of unsymmetrical diaryl chalcogenides
作者:Debasish Kundu、Sabir Ahammed、Brindaban C. Ranu
DOI:10.1039/c2gc35328h
日期:——
A convenient, general and efficient procedure for the synthesis of unsymmetrical diaryl chalcogenides has been developed by the reaction of aryl diazonium fluoroborates and diaryl dichalcogenides in the presence of zinc dust in dimethyl carbonate under microwave irradiation. The reactions of a wide range of substituted aryl diazonium fluoroborates and diaryl dichalcogenides have been addressed. The
CuO nanoparticles: an efficient and recyclable catalyst for cross-coupling reactions of organic diselenides with aryl boronic acids
作者:Diego Alves、Cayane G. Santos、Márcio W. Paixão、Letiére C. Soares、Diego de Souza、Oscar E.D. Rodrigues、Antônio L. Braga
DOI:10.1016/j.tetlet.2009.09.052
日期:2009.12
We present here an efficient and ligand-free cross-coupling reaction of organic diselenides with aryl boronicacids using a catalytic amount of CuO nanoparticles in DMSO at 100 °C under air atmosphere. This is a general cross-coupling reaction and was performed with organic diselenides and aryl boronicacids bearing electron-withdrawing and electron-donating groups affording the corresponding selenides
Enantiomerically pure organoseleno-1-arylethanols by enzymatic resolution with Candida antarctica lipase: Novozym 435
作者:Álvaro T. Omori、Leonardo F. Assis、Leandro H. Andrade、João V. Comasseto、André L.M. Porto
DOI:10.1016/j.tetasy.2007.04.019
日期:2007.5
Racemic organoseleno-1-arylethanols were prepared by ortho-lithiation of arylethanols, followed by sequential reaction with elemental selenium and alkyl halides and by reaction of either aryldiazonium chlorides with diphenyldiselenide or with lithium and magnesium alkylselenolates. Enantiomerically enriched organoseleno-1-arylethanols were obtained by kinetic resolution of the racemic mixtures by esterification catalyzed by Candida antarctica lipase (Novozym 435). In some cases, enantiomeric excesses of up to 99% were obtained both for alcohols and acetates. (C) 2007 Elsevier Ltd. All rights reserved.