Adeyemi A, Odell LR, Larhed M. Regio- and Stereoselective Synthesis of Allylic Spiroethers (Spirobenzofuranes) via an Intramolecular Mizoroki-Heck Reaction.
J Org Chem 2020;
85:7648-7657. [PMID:
32083867 DOI:
10.1021/acs.joc.9b03329]
[Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The palladium(0)-catalyzed intramolecular annulation of 12 1,3-disubstituted cyclopentenes, derived from (+)-vince lactam, resulted in 5-exo cyclizations which furnished a series of 2,5-dimethyl-1-((3R,4'S)-2H-spiro[benzofuran-3,1'-cyclopentan]-2'-en-4'-yl)-1H-pyrroles in excellent diastereoselectivities and useful isolated yields. The double bond migration process that followed the arylpalladium insertion was controlled by a fine-tuning of the reaction system, which provided regioselectivities of up to 98:2. The selective Mizoroki-Heck reaction was used as the key transformation for preparing two new spirocyclic monoprotected amino acids as single stereoisomers.
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