Enantioselective Synthesis of 2-Methyl-1,2-syn- and 2-Methyl-1,2-anti-3-butenediols via Allene Hydroboration−Aldehyde Allylboration Reaction Sequences

The hydroboration of allene 7 with ( d Ipc)2BH at 0 °C provides the kinetic allylborane 12Z with >20:1 selectivity. However, when the hydroboration is performed at 85 °C, the kinetically formed allylborane isomerizes to give the thermodynamic allylborane 12E with ≥12:1 selectivity. Subsequent tre...

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Bibliographic Details
Published in:Journal of the American Chemical Society 2009-10, Vol.131 (41), p.14602-14603
Main Authors: Chen, Ming, Handa, Masaki, Roush, William R
Format: Article
Language:English
Subjects:
Alcohols - chemical synthesis
Alcohols - chemistry
Aldehydes - chemistry
Alkadienes - chemistry
Boron - chemistry
Stereoisomerism
Substrate Specificity
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Summary:The hydroboration of allene 7 with ( d Ipc)2BH at 0 °C provides the kinetic allylborane 12Z with >20:1 selectivity. However, when the hydroboration is performed at 85 °C, the kinetically formed allylborane isomerizes to give the thermodynamic allylborane 12E with ≥12:1 selectivity. Subsequent treatment of 12Z or 12E with aldehydes at −78 °C, followed by oxidative workup, provides the 2-methyl-1,2-diols 8 and 9 in good yield and with 80−92% e.e.
ISSN:0002-7863
1520-5126
DOI:10.1021/ja904599h