Asymmetric Hydrogenation of Ketones and Enones with Chiral Lewis Base Derived Frustrated Lewis Pairs
作者:Bochao Gao、Xiangqing Feng、Wei Meng、Haifeng Du
DOI:10.1002/anie.201914568
日期:2020.3.9
The concept of frustratedLewispairs (FLPs) has been widely applied in various research areas, and metal-free hydrogenation undoubtedly belongs to the most significant and successful ones. In the past decade, great efforts have been devoted to the synthesis of chiral boron Lewis acids. In a sharp contrast, chiral Lewisbase derived FLPs have rarely been disclosed for the asymmetric hydrogenation.
Straightforward Synthesis of Enantiopure 2,3-Dihydrobenzofurans by a Sequential Stereoselective Biotransformation and Chemical Intramolecular Cyclization
A new family of opticallyactive 2,3-dihydrobenzofurans has been prepared by a simple chemoenzymatic asymmetric strategy. This synthetic approach is based on the combination of a lipase-mediated kinetic resolution of 1-aryl-2-propanols or bioreduction of the corresponding ketones followed by an intramolecular cyclization reaction. These novel compounds have been prepared in enantiopure form and in
Compounds of formula (I), wherein X and R
1
-R
6
, are as defined in the claims, exhibit alpha2 agonistic activity and thus are useful as alpha2 agonists, especially as alpha2A agonists. Methods of use of said compounds are also provided.