Premium
Gold(I)‐Catalyzed Regiodivergent Rearrangements: 1,2‐ and 1,2′‐Alkyl Migration in Skipped Alkynyl Ketones
Author(s) -
Li Wenbo,
Li Yuying,
Zhou Guanghua,
Wu Xiangshu,
Zhang Junliang
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201201727
Subject(s) - chemistry , alkyl , regioselectivity , cyclopentene , stereospecificity , cationic polymerization , catalysis , cleavage (geology) , ring (chemistry) , stereochemistry , medicinal chemistry , selectivity , organic chemistry , geotechnical engineering , fracture (geology) , engineering
Abstract A series of 2‐alkynyl carbonyl compounds that contain a cyclopentene ring or a heterocycle can be transformed into various fused dihydrobenzofurans and tetrahydrofuro[2,3‐ c ]pyridines by means of a 1,2‐alkyl migration process. Both of these reactions proceed with excellent regioselectivity and stereospecificity when using a cationic gold(I) catalyst. Treatment of 4‐styrylcyclopent‐1‐enecarboxylates under different conditions affords a range of highly functionalized dihydrobenzofurans and dihydroisobenzofurans. A divergence in product selectivity, which depends on the anion of the silver salts used, was observed. Interestingly, ring‐fused tetrahydroquinolines undergo only 1,2′‐alkyl migration reaction by means of a CC cleavage/cyclization sequence to provide tetrahydroazepine derivatives. Mechanistic studies suggest that the gold complexes catalyze 1,2‐alkyl migration reactions through a concerted reaction pathway and 1,2′‐alkyl migration reactions through a stepwise reaction pathway.