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Propargyl Claisen Rearrangement

By: William Sommer, Aldrich ChemFiles 2009, 9.5, 8.

Aldrich ChemFiles 2009, 9.5, 8.

In 2004, Toste and coworkers reported the use of the gold catalyst [(Ph3PAu)3O]BF4 which provides access to a variety of homoallenic alcohols via a rapid two-step, one-pot sequence of a Claisen rearrangement of a propargyl vinyl ether followed by reduction of the aldehyde functionality. The reactions are generally high yielding and the robust catalyst system also shows superb ability to relay resident chirality into the allene products. Only 1 mol % of catalyst is needed for this transformation. Substitution at the alkyne is well tolerated generating the desired allenes in high yields (Scheme 1).

Scheme 1

Scheme 1

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Materials

     

References

  1. Sherry, B. D. et al. J. Am. Chem. Soc. 2004, 126, 15978.

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