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DOI: 10.1055/s-0034-1378421
Asymmetric Synthesis of Vicinal Amino Alcohols by Rhodium Catalysis
Publication History
Publication Date:
18 July 2014 (online)
Significance
α-Aminoboronic acid derivatives are useful organometallic reagents for the convergent, asymmetric synthesis of substituted amine compounds. There is however no example of rhodium-catalyzed additions of α-heteroatom-substituted boron reagents to electrophiles. The authors report the first rhodium-catalyzed coupling of α-aminoboronic acid derivatives by addition to carbonyl compounds for the convergent, asymmetric synthesis of vicinal amino alcohols.
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Comment
The highlight of this work is that the rhodium-catalyzed addition of protected α-amino trifluoroborates to aryl and alkenyl trifluoromethyl ketones proceeds in good yields and with good diastereoselectivity, without affecting the α-amino stereocenter. Further, the authors reveal that the tert-butanesulfonyl-, pivaloyl- and trifluoroacetyl-nitrogen substituents influence both yield and stereoselectivity. Although unactivated carbonyls such as acetone or benzaldehyde couple with very poor efficiency/selectivity, isatin shows exceptionally good selectivity.
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