Development of a New Lewis Acid-Catalyzed [3,3]-Sigmatropic Rearrangement: The Allenoate-Claisen Rearrangement
Abstract
A new Lewis acid-catalyzed Claisen rearrangement has been developed that allows the stereoselective construction of β-amino-α,β,ε,ζ-unsaturated-γ,δ-disubstituted esters from simple allylic amines and allenoate esters. This reaction, which is contingent upon the use of Lewis acid, can be conducted with a range of metal salts (Yb(OTf)_3, AlCl_3, Sn(OTf)_2, Cu(OTf)_2, MgBr_2·Et_2O, FeCl_3, Zn(OTf)2) with catalyst loadings as low as 5 mol %. This catalytic process provides access to a diverse range of β-amino-α,β,ε,ζ-unsaturated-γ,δ-disubstituted esters in high yield and with excellent levels of diastereoselectivity for a series of allyl pyrrolidines (R_1 = H, Me, i-Pr, Ph, NR_2 = pyrrolidine, piperidine, Nme_2; ≥81% yield, ≥94:6 syn:anti) and allenoate esters (R_2 = H, Me, i-Pr, Ph, allyl, NPht, Cl; ≥75% yield, ≥91:9 syn:anti). The capacity of this new Claisen rearrangement to provide catalytic access to elusive structural motifs has also been demonstrated in the stereospecific formation of quaternary carbon bearing frameworks arising from geranyl- and neryl pyrrolidine (≥93% yield, >98:2 dr).
Additional Information
© 2002 American Chemical Society. Received August 9, 2002. Publication Date (Web): October 29, 2002. Support was provided by the NIHGMS (R01 GM61214-01) and the UC-AIDS Research Program. We are grateful to Dr. T. P. Yoon (Harvard University) for helpful discussions.Attached Files
Supplemental Material - ja028090q-2_s1.pdf
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Additional details
- Eprint ID
- 75272
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- CaltechAUTHORS:20170321-110525126
- NIH
- R01 GM61214-01
- University of California AIDS Research Program
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2017-03-21Created from EPrint's datestamp field
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2021-11-15Created from EPrint's last_modified field