A Convenient Triisobutylaluminium (TIBAL)-Promoted Johnson-Claisen Approach to γ,δ-Unsaturated Alcohols
Kelly L. Cosgrove, Ross P. McGeary*
*School of Chemistry and Molecular Biosciences, The
University of Queensland, Brisbane, Queensland 4072, Australia, Email: r.mcgeary
uq.edu.au
K. L. Cosgrove, R. P. McGeary, Synlett, 2009, 1749-1752.
DOI: 10.1055/s-0029-1217382
Abstract
Mixed ortho esters derived from allylic alcohols undergo methanol elimination in the presence of triisobutylaluminium (TIBAL) at room temperature to form mixed ketene acetals. TIBAL then promotes immediate Claisen rearrangement of and a subsequent reduction of the ester products in the presence of DIBAL, to give unsaturated γ,δ-primary alcohols in a convenient, one-pot procedure.
see article for more examples
proposed reaction pathway
An Efficient and Solvent-Free Synthesis of Mixed Ortho Esters
K. L. Cosgrove, R. P. McGeary, Synlett, 2008, 2425-2428.
Key Words
Johnson-Claisen Rearrangement, triisobutylaluminium, mixed ortho esters, ketene dimethyl acetal, γ,δ-unsaturated alcohols
ID: J60-Y2009-1930
