Rhodium carbenoid-initiated Claisen rearrangement: scope and mechanistic observations.
[formula: see text] It has been shown that alpha-diazoketones react with allylic alcohols in the presence of Rh(II) catalysts to furnish intermediate enols which subsequently undergo Claisen rearrangement to alpha-hydroxyketones. Herein we report (1) studies into the mechanism of this transformation which establish that Claisen rearrangement is neither rhodium- nor acid-catalyzed but a reaction intrinsic to the intermediate enols that proceeds at a rate governed by enol substituents (R3, R4, R5) and (2) the reaction of alpha-diazoketones with propargylic alcohols and preliminary investigations into its scope and mechanism.
Wood
J L
JL
Sterling Chemistry Laboratory, Yale University, New Haven, Connecticut 06520-8107, USA. john.wood@yale.edu
Moniz
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GA
D018360:Crystallography, X-Ray; D007659:Ketones / Q000138:chemical synthesis*; D012238:Rhodium / Q000737:chemistry*
D007659:Ketones; D012238:Rhodium