介绍了一系列新型有机催化剂的设计、制备和研究。催化剂的设计灵感来自于 DNA 核碱基发展精确和明确的氢键的能力。我们已经表明,这种现象可用于创建一种有用的有机催化剂,该催化剂显示出类似于常见有机底物的识别模式。基于鸟嘌呤结构的选定双功能催化剂已被证明可催化 1,3-二羰基化合物与各种硝基烯烃的共轭加成,从而以良好的产率和对映选择性提供产品。
介绍了一系列新型有机催化剂的设计、制备和研究。催化剂的设计灵感来自于 DNA 核碱基发展精确和明确的氢键的能力。我们已经表明,这种现象可用于创建一种有用的有机催化剂,该催化剂显示出类似于常见有机底物的识别模式。基于鸟嘌呤结构的选定双功能催化剂已被证明可催化 1,3-二羰基化合物与各种硝基烯烃的共轭加成,从而以良好的产率和对映选择性提供产品。
The invention relates to a process for producing a trifluotomethylbenzylamine represented by the following general formula (1),
1
where each R independently represents a halogen selected from the group consisting of fluorine, chlorine, bromine and iodine, an alkyl group having a carbon atom number of 1-4, an alkoxy group having a carbon atom number of 1-4, an amino group, a hydroxyl group or a trifluoromethyl group, and n represents an integer from 0 to 4. The process includes hydrogenating a trifluoromethylbenzonitrile by hydrogen in an organic solvent in the presence of ammonia and a catalyst containing a platinum group element. This trifluoromethylbenzonitrile is represented by the following general formula (2),
2
where R and n are defined as above. With this process, it is possible to obtain the trifluoromethylbenzylamine at an extremely high yield.
Cooperative Thiourea–Brønsted Acid Organocatalysis: Enantioselective Cyanosilylation of Aldehydes with TMSCN
作者:Zhiguo Zhang、Katharina M. Lippert、Heike Hausmann、Mike Kotke、Peter R. Schreiner
DOI:10.1021/jo201864e
日期:2011.12.2
We report a new thiourea-Bronsted acid cooperative catalytic system for the enantioselective cyanosilylation of aldehydes with yields up to 90% and enamioselectivities up to 88%. The addition of an achiral acid was found to be crucial for high asymmetric induction. Mechanistic investigations using a combination of NMR, ESI-MS, and density functional theory computations (including solvent corrections) at the M06/6-31G(d,p) level of theory suggest that the key catalytic species results from the cooperative interaction of bifunctional thioureas and an achiral acid that form well-defined chiral hydrogen-bonding environments.
Tomioka, Yukihiko; Ohkubo, Kimiko; Yamazaki, Motoyoshi, Chemical and pharmaceutical bulletin, 1985, vol. 33, # 4, p. 1360 - 1366