A new dinuclear chiral salen complexes for asymmetric ring opening and closing reactions: Synthesis of valuable chiral intermediates
作者:Santosh Singh Thakur、Shu-Wei Chen、Wenji Li、Chang-Kyo Shin、Seong-Jin Kim、Yoon-Mo Koo、Geon-Joong Kim
DOI:10.1016/j.jorganchem.2005.12.044
日期:2006.4
A new dinuclear chiral Co(salen) complexes bearing group 13 metals have been synthesized and characterized. The easily prepared complexes exhibited very high catalytic reactivity and enantioselectivity for the asymmetric ring opening of epoxides with H2O, chloride ions and carboxylic acids and consequently provide enantiomerically enriched terminalepoxides (>99% ee). It also catalyzes the asymmetric
Olefinmetathesis as a tool for multinuclear Co(<scp>iii</scp>)salen catalyst construction: access to cooperative catalysts
作者:Robert M. Haak、Marta Martínez Belmonte、Eduardo C. Escudero-Adán、Jordi Benet-Buchholz、Arjan W. Kleij
DOI:10.1039/b911856j
日期:——
Co(III)salencatalysts is reported. Olefin metathesis has been used as a key construction tool for the multimetallic structures starting from versatile allyl-substituted salen scaffolds. The Co(III) complexes were tested in the hydrolytickineticresolution of (rac)-1,2-epoxyhexane and epoxide ring opening reactions using methanol as the nucleophile. The preliminary results suggest a cooperative mode
Highly active oligomeric Co(salen) catalysts for the asymmetric synthesis of α-aryloxy or α-alkoxy alcohols via kinetic resolution of terminal epoxides
作者:Xunjin Zhu、Krishnan Venkatasubbaiah、Marcus Weck、Christopher W. Jones
DOI:10.1016/j.molcata.2010.06.015
日期:2010.8.17
alcohols. The catalyst is compared to other dimeric, oligomeric and monomeric Co(salen) complexes including a pimelate-linked macrocyclic Co(salen) catalyst and a dimeric Co(salen) catalyst referred to as a bisalen. The catalysts that contain multiple Co(salen) units within a single molecular framework allow for substantial decreases in catalyst loading compared with the monomeric catalyst. The cyclooctene-based