Iridium-Catalyzed Highly Enantioselective Transfer Hydrogenation of Aryl N-Heteroaryl Ketones with N-Oxide as a Removable ortho-Substituent.
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| Abstract | :  A highly enantioselective transfer hydrogenation of non-ortho-substituted aryl N-heteroaryl ketones, using readily available chiral diamine-derived iridium complex (S,S)-1f as a catalyst and sodium formate as a hydrogen source in a mixture of H2O/i-PrOH (v/v = 1:1) under ambient conditions, is described. The chiral aryl N-heteroaryl methanols were obtained with up to 98.2% ee by introducing an N-oxide as a removable ortho-substituent. In contrast, no more than 15.1% ee was observed in the absence of an N-oxide moiety. Furthermore, the practical utility of this protocol was also demonstrated by gram-scale asymmetric synthesis of bepotastine besilate in 51% total yield and 99.9% ee. | 
| Year of Publication | :  2018 | 
| Journal | :  Organic letters | 
| Date Published | :  2018 | 
| ISSN Number | :  1523-7060 | 
| URL | :  https://dx.doi.org/10.1021/acs.orglett.7b03878 | 
| DOI | :  10.1021/acs.orglett.7b03878 | 
| Short Title | :  Org Lett | 
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