The Carroll rearrangement (1940) in the presence of
base and with high reaction temperature (path A) takes place through an intermediate
enol which then rearranges in a sigmatropic Claisen rearrangement. The follow-up is a decarboxylation. With
palladium(0) as a
catalyst, the reaction (Tsuji, 1980) is much milder (path B) with an intermediate allyl cation / carboxylic acid anion
organometallic complex.[2]
This reaction delivers the main
enantiomer with 88%
enantiomeric excess. It remains to be seen if this reaction will have a wide scope because the
acetamido group appears to be a prerequisite.
The same catalyst but a different ligand is employed in this
enantioconvergent reaction:[6]
^Carroll, M. F. "131. Addition of α,β-unsaturated alcohols to the active methylene group. Part I. The action of ethyl acetoacetate on linalool and geraniol". Journal of the Chemical Society1940, 704–706.
doi:
10.1039/JR9400000704
^Palladium-catalyzed rearrangement of allylic esters of acetoacetic acid to give γ,δ-unsaturated methyl ketonesTetrahedron Letters, Volume 21, Issue 33, 1980, Pages 3199-3202 Isao Shimizu, Toshiro Yamada and
Jiro Tsujidoi:
10.1016/S0040-4039(00)77444-2
^
abAsymmetric Allylic Alkylation of Ketone Enolates: An Asymmetric Claisen Surrogate Erin C. Burger and Jon A. Tunge
Org. Lett.; 2004; 6(22) pp 4113 - 4115; (Letter)
doi:
10.1021/ol048149t
^Kuwano, R.; Ishida N.; Murakami, M. "Asymmetric Carroll rearrangement of allyl α-acetamido-β-ketocarboxylates catalysed by a chiral palladium complex". Chemical Communications2005, (31), 3951–3952.
doi:
10.1039/b505105c
^Deracemization of Quaternary Stereocenters by Pd-Catalyzed Enantioconvergent Decarboxylative Allylation of Racemic b-Ketoesters Justin T. Mohr, Douglas C. Behenna, Andrew M. Harned, and Brian M. Stoltz Angew. Chem. Int. Ed. 2005, 44, 6924 –6927
doi:
10.1002/anie.200502018