Rhodium-catalyzed asymmetric 1,4-addition of arylboron compounds generated in situ from aryl bromides

Rhodium-catalyzed asymmetric 1,4-addition to α,β-unsaturated ketones is effected by use of arylborates, generated in situ by lithiation of aryl bromides followed by treatment with trimethoxyborane, to give the corresponding β-aryl ketones of up to 99% ee in high yields. The addition of 1 equiv. (to...

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Bibliographic Details
Published in:Tetrahedron letters 1999-09, Vol.40 (38), p.6957-6961
Main Authors: Takaya, Yoshiaki, Ogasawara, Masamichi, Hayashi, Tamio
Format: Article
Language:English
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Summary:Rhodium-catalyzed asymmetric 1,4-addition to α,β-unsaturated ketones is effected by use of arylborates, generated in situ by lithiation of aryl bromides followed by treatment with trimethoxyborane, to give the corresponding β-aryl ketones of up to 99% ee in high yields. The addition of 1 equiv. (to arylborate) of water is essential for high chemical yields. Asymmetric reaction of enones with arylborates, generated in situ from aryl bromides, proceeded in the presence of 0.1∼3 mol % of rhodium-binap catalyst and water to give the corresponding 1,4-addition products of up to 99% ee in high yields.
ISSN:0040-4039
1873-3581
DOI:10.1016/S0040-4039(99)01412-4