Candida antarctica lipase A and Pseudomonas stutzeri lipase as a pair of stereocomplementary enzymes for the resolution of 1,2-diarylethanols and 1,2-diarylethanamines
摘要:
Candida antarctica lipase A (CALA) and Pseudomonas stutzeri lipase (PSL) displayed opposite enantioselectivities in the acylation of 1,2-diphenylethanol and 1,2-diphenylethanamine. CALA was (S)-selective while PSL was (R)-selective. In addition, fourteen different 1,2-diarylethanols were tested as the substrates of CALA. It was found that most of them were accepted by CALA with high enantioselectivity. The DKR of five representative substrates by the combination of CALA and a ruthenium-based racemization catalyst provided good yields (82-91%) and acceptable enantiopurities (87-94% ee). (C) 2012 Elsevier Ltd. All rights reserved.
Ring-opening of epoxides furnishing either linear or branched products belongs to the group of classic transformations in organic synthesis. However, the regioselective cross-electrophile coupling of aryl epoxides with aryl halides still represents a key challenge. Herein, we report that the vitamin B12/Ni dual-catalytic system allows for the selective synthesis of linear products under blue-light
提供线性或支化产物的环氧化物的开环属于有机合成中的经典转化组。然而,芳基环氧化物与芳基卤化物的区域选择性交叉亲电偶联仍然是一个关键挑战。在此,我们报告了维生素 B 12 /Ni 双催化系统允许在蓝光照射下选择性合成线性产物,从而补充获得支化醇的方法。实验和理论研究证实了所提出的涉及烷基钴胺素作为该反应中间体的机制。
Preparation of Asymmetric Phase-transfer Catalyst, 1,4-Bis((4S,5S)-1,3-bis(3,5-di-tert-butylbenzyl)-4,5-diphenylimidazolidin-2-ylidene)piperazine-1,4-diium chloride