Unprecedented Catalytic Asymmetric Reduction of N−H Imines
摘要:
Addition of lithium bis(trimethylsilyl)amide to perfluorinated ketones 1a-j affords (E)-N-TMS-ketimines 2a-j that are reduced in situ to afford racemic perfluoromethylated amine hydrochloride salts 3a-j in 54-97% yields. Solvolysis of the N-Si bond in MeOH leads to formation of bench-stable, isolable N-H imine Z/E isomer mixtures along with a methanol adduct. Enantioselective reduction of these three-component mixtures provides the first catalytic asymmetric synthesis of trifluoromethylated amines in 72-95% yields and 75-98% ee.
Here we have successfully demonstrated the first stereodivergent direct nucleophilic trifluoromethylation of N-sulfinylimines using the potent greenhouse gas “HFC-23, fluoroform” with an organic-superbase or an organometallic-base in high yields and selectivity.
Asymmetric Synthesis of Trifluoromethylated Amines via Catalytic Enantioselective Isomerization of Imines
作者:Yongwei Wu、Li Deng
DOI:10.1021/ja306771n
日期:2012.9.5
A new approach toward the asymmetric synthesis of optically active trifluoromethylated amines was enabled by an unprecedented, highly enantioselective catalytic isomerization of trifluoromethyl imines with a new chiral organic catalyst. Not only aryl but also alkyl trifluoromethylated amines could be obtained in high enantioselectivities.
One-pot asymmetric synthesis of α-trifluoromethylated amines from α-trifluoromethyl ketones
作者:Jian Xu、Zhen-Jiang Liu、Xian-Jin Yang、Li-Min Wang、Guan-Long Chen、Jin-Tao Liu
DOI:10.1016/j.tet.2010.09.047
日期:2010.11
of (Rs)-N-tert-butanesulfinyl α-trifluoromethyl ketimines formed in situ from the corresponding α-trifluoromethyl ketones and N-tert-butanesulfinamide has been achieved, and either diastereomer of N-tert-butanesulfinyl α-trifluoromethyl amines was obtained in good yields with excellent diastereoselectivities (up to 99:1 dr) using NaBH4 and L-Selectride as the reductants, respectively.
The ruthenium-catalyzed asymmetric reductiveamination of aryl-trifluoromethyl ketones affording high value primary α-(trifluoromethyl)arylmethylamines using cheap NH4OAc as the nitrogen source and H2 as the reductant is reported. This user-friendly and simple catalytic method tolerates various aromatic functions with electron-withdrawing or -donating substituents at the para- or meta-positions and