title: N-Heterocyclic Carbene-Catalyzed Intramolecular Nucleophilic Substitution: Enantioselective Construction of All-Carbon Quaternary Stereocenters.
abstract: An efficient enantioselective N-heterocyclic carbene (NHC)-catalyzed intramolecular SN2' nucleophilic substitution of aldehydes with (E/Z)-trisubstituted allylic bromides was accomplished. A range of enantioenriched chromanones bearing an all-carbon quaternary stereocenter at the C3 position were prepared with up to 97 % yield and 98 % enantiomeric excess. The resulting vinyl and carbonyl groups in these products can be transformed into a variety of synthetically important building blocks.
authors.affiliation: Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Department of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China.
authors.forename: Ming
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Department of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Department of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Yang
authors.affiliation: Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of Ministry of Education, Department of Chemistry and Materials Science, Northwest University, Xi'an, 710127, P. R. China.
authors.forename: Ling
authors.initials: L
authors.lastname: Zhou
keywords: asymmetric catalysis; carbenes; enantioselectivity; nucleophilic substitution; organocatalysis