Open AccessSwitchable Diastereoselectivity in the Fluoride-Promoted Vinylogous Mukaiyama–Michael Reaction of 2-[(Trimethylsilyl)oxy]furan Catalyzed by Crown Ethers
Author(s) -
Giorgio Della Sala,
Marina Sicignano,
Rosaria Schettini,
Francesco De Riccardis,
Luigi Cavallo,
Yury Minenkov,
Chloé Batisse,
Gilles Hanquet,
Frédéric R. Leroux,
Irene Izzo
Publication year - 2017
Publication title -
the journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.2
H-Index - 228
eISSN - 1520-6904
pISSN - 0022-3263
DOI - 10.1021/acs.joc.7b00743
Subject(s) - furan , trimethylsilyl , chemistry , diastereomer , catalysis , adduct , michael reaction , toluene , solvent , organic chemistry , fluoride , medicinal chemistry , crown ether , ion , inorganic chemistry
The fluoride-promoted vinylogous Mukaiyama-Michael reaction of 2-[(trimethylsilyl)oxy]furan with diverse α,β-unsaturated ketones is described. The TBAF-catalyzed VMMR afforded high anti-diastereoselectivity irrespective of the solvents used. The KF/crown ethers catalytic systems proved to be highly efficient in terms of yields and resulted in a highly diastereoselective unprecedented solvent/catalyst switchable reaction. Anti-adducts were obtained as single diastereomers or with excellent diastereoselectivities when benzo-15-crown-5 in CH 2 Cl 2 was employed. On the other hand, high syn-diastereoselectivities (from 73:27 to 96:4) were achieved by employing dicyclohexane-18-crown-6 in toluene. On the basis of DFT calculations, the catalysts/solvent-dependent switchable diastereoselectivities are proposed to be the result of loose or tight cation-dienolate ion pairs.
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