Synthesis of chiral sulfonamide/Schiff base ligands
摘要:
We report a facile two step synthesis of chiral ligands for bonding to transition-metals. The ligands are easily prepared from trans-1,2-diaminocycrohexane by reaction with sulfonyl chlorides to give amino-sulfonamide compounds. These intermediates are then condensed with salicylaldehyde derivatives to provide sulfonamide/Schiff base compounds which represent a new class of chiral ligands. (C) 1998 Elsevier Science Ltd. All rights reserved.
Asymmetric Synthesis of Polysubstituted 4-Amino- and 3,4-Diaminochromanes with a Chiral Multifunctional Organocatalyst
作者:Wenduan Hou、Bo Zheng、Jun Chen、Yungui Peng
DOI:10.1021/ol300798t
日期:2012.5.4
A series of multifunctional catalysts with two chiral diaminocyclohexane units were developed and successfully applied in the asymmetricoxa-Michael–aza-Henrycascadereaction of salicylaldimines with nitroolefins. This approach provides a simple and efficient entry to polysubstituted chiral 4-aminobenzopyrans with three consecutive stereocenters and in high yield (up to 97%) with excellent stereoselectivity
This work disclosed a highly enantioselective hydrogenation of non-ortho-substituted 2-pyridyl arylketones via Ir/f-diaphos catalysis. This catalytic system allows for full control over the configuration of the stereocenter, affording two enantiomers of the desired products with extremely high enantioselectivity (up to >99% ee in most cases) and excellent reactivity (TON of up to 19600, TOF of 1633
The iridium/f-diaphos L1, L5 or L12 catalyzed asymmetric hydrogenation of 2-imidazolyl aryl/alkyl ketones to afford two enantiomers of the desired chiral alcohols with high conversions (up to 99% yield) and moderate to excellent enantioselectivities (61% - >99% ee) was realized for the first time. This protocol could be easily conducted on a gram-scale with a TON of 9700.
铱/ f-二磷L1、L5或L12催化 2-咪唑基芳基/烷基酮的不对称氢化,得到所需手性醇的两种对映异构体,具有高转化率(高达 99% 的产率)和中等至优异的对映选择性(61% - >99% ee ) 首次实现。该协议可以在 TON 为 9700 的克级上轻松执行。