Regio- and Stereoselective Synthesis of Allylic Spiroethers (Spirobenzofuranes) via an Intramolecular Mizoroki-Heck Reaction.

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Adeyemi A, Odell LR, Larhed M

J. Org. Chem. 85 (12) 7648-7657 [2020-06-19; online 2020-06-01]

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.

PubMed 32083867

DOI 10.1021/acs.joc.9b03329

Crossref 10.1021/acs.joc.9b03329