activities (up to 9800 TON; TON=turnover number), broad substrate scope (81 examples), good functional‐group tolerance, and excellent enantioselectivities (85–98 % ee) in the hydrogenation of various ketones. These aspects are rare in earth‐abundant metal catalyzed hydrogenations. The utility of the protocol have been demonstrated in the asymmetric synthesis of a variety of key intermediates for chiral drugs
已经开发了一系列含有基于核苷的手性钳式配体的Mn I配合物,这些配合物具有模块化和可调的结构。该配合物在各种酮的氢化反应中显示出前所未有的高活性(高达9800 TON; TON =周转数),广泛的底物范围(81个实例),良好的官能团耐受性和出色的对映选择性(85-98%ee)。这些方面在稀土金属催化的氢化反应中很少见。该协议的实用性已在手性药物的多种关键中间体的不对称合成中得到证明。初步的机理研究表明,底物与催化剂相互作用的外层模式可能主导了催化作用。
Catalyzed asymmetric aryl transfer reactions to aldehydes with boroxines as aryl source
作者:Xiaoyu Wu、Xinyuan Liu、Gang Zhao
DOI:10.1016/j.tetasy.2005.06.010
日期:2005.7
Asymmetricaryltransfer of triphenylboroxin to a set of arylaldehydes has been carried out in the presence of chiral amino alcohols derived from (S)-proline with high enantioselectivity. Substituted phenyl boroxins were also used as arylsource in asymmetric arylation of benzaldehyde.
directing group (bromo group) showcased the potential application of this substrate‐controlled bioreduction reaction. The combined use of substrateengineering and protein engineering, was demonstrated to be a useful strategy in efficiently improving stereoselectivity or switching stereopreference of enzymatic processes.
Ligand design by‐pam: A ruthenium‐catalyzed asymmetric arylation of aldehydes with arylboronicacids has been developed, giving chiral diarylmethanols in good yields. The use of a chiral bidentate phosphoramidite ligand ((R,R)‐Me‐bipam) led to excellent enantioselectivities.
Synthesis of modular thiophene-oxazoline ligands and their application in the asymmetric phenyl transfer reaction to aldehydes
作者:Zhuo Chai、Xin-Yuan Liu、Xiao-Yu Wu、Gang Zhao
DOI:10.1016/j.tetasy.2006.09.004
日期:2006.9
A series of thiophene mono (oxazoline) N,O-ligands with three sites of diversity were synthesized concisely in two steps from the corresponding thiophene carbonitriles. These ligands were applied to the enantioselective phenyl transfer reaction of aldehydes, resulting in the corresponding chiral diaryl methanol products with excellent yields and moderate to good enantioselectivities.