Rinaldi A, Langé V, Scarpi D, Occhiato EG. One-Pot Access to 1,7a-Dihydro-1,3a-ethano-indene and 1,8a-Dihydro-1,3a-ethano-azulene Skeletons by a Sequential Gold(I)-Catalyzed Propargyl Claisen Rearrangement/Nazarov Cyclization/[4+2] Cycloaddition Reaction.
J Org Chem 2020;
85:5078-5086. [PMID:
32192345 DOI:
10.1021/acs.joc.0c00088]
[Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
An efficient synthetic approach to the tricyclic 1,7a-dihydro-1,3a-ethano-indene and 1,8a-dihydro-1,3a-ethano-azulene skeletons from suitable propargyl vinyl ethers is based on a one-pot, multistep process entailing a gold(I)-catalyzed propargyl Claisen rearrangement/Nazarov cyclization, a [4+2] cycloaddition of the formed six- or seven-membered ring-fused cyclopentadiene system, and a final protection step for the easy isolation and purification of the products by chromatography.
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