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Please login to access the full content or check if you have access via23.14.1.2.2.4 Variation 4: Aldols via Boron Enolates from the Addition of Sulfur Nucleophiles to Monoalkylketenes
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Tidwell, T. T., Science of Synthesis, (2006) 23, 596.
Methylketene (2) prepared by dehalogenation of 2-bromopropanoyl bromide reacts with dibutyl(tert-butylsulfanyl)borane (156) by addition of the sulfur nucleophile anti to the methyl group of the ketene to form the intermediate enol borinate 157, which reacts with aldehydes 158 [R1 = Ph, iPr, (CH2)2Ph] to form aldol products 159 in 65–78% yield and with erythro/threo ratios of 93:3 to >95:5 (Scheme 49).[109] Enol borinates prepared by enolization of S-tert-butyl propanethioate have the opposite stereochemistry and react to form the threo-products preferentially.[109]
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References
| [109] | Meeeee, M.; Meeeeeee, M., Meeeeeeeeee Meee., (8888), 8888. |
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