Vale J, Gomes RF, Afonso CAM, Candeias NR. Functionalized Cyclopentenes via the Formal [4+1] Cycloaddition of Photogenerated Siloxycarbenes from Acyl Silanes.
J Org Chem 2022;
87:8910-8920. [PMID:
35736215 PMCID:
PMC9776530 DOI:
10.1021/acs.joc.2c00591]
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Abstract
This work describes the first formal cycloaddition reaction of photogenerated nucleophilic carbenes derived from acylsilanes with electrophilic dienes. The resulting transient donor-acceptor cyclopropane rearranges to its stable and highly functionalized cyclopentene isomer in an unprecedented metal-free process. The cyclopropanation-vinyl cyclopropane rearrangement sequence was corroborated by computational calculations. The cyclopropane formation corresponds to a higher energetic barrier, and the vinylcyclopropane-cyclopentene rearrangement proceeds through different mechanisms, although of comparable energies, depending on the stereochemistry of the cyclopropane.
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