title: Access to thiopyrano[2,3-b]indole via tertiary amine-catalyzed formal (3+3) annulations of β'-acetoxy allenoates with indoline-2-thiones.
abstract: DABCO-catalyzed formal (3+3) annulations of β'-acetoxy allenoates with indoline-2-thiones are described, which provide facile access to thiopyrano[2,3-b]indole under mild reaction conditions. The reaction might proceed via the SN2'-SN2'-type process between β'-acetoxy allenoate and indole-2-thiolate with the assistance of the DABCO catalyst and K2CO3additive, followed by intramolecular Friedel-Crafts reaction at the 3-position of indole and central carbon of allene.
authors.affiliation: College of Chemistry and Molecular Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237, China.
authors.forename: Chunjie
authors.initials: C
authors.lastname: Ni
authors.affiliation: Jiangsu Key Laboratory of Advanced Catalytic Materials & Technology, School of Petrochemical Engineering, Changzhou University, 1 Gehu Road, Changzhou 213164, China. txf@cczu.edu.cn.
authors.forename: Yuwen
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Jiangsu Key Laboratory of Advanced Catalytic Materials & Technology, School of Petrochemical Engineering, Changzhou University, 1 Gehu Road, Changzhou 213164, China. txf@cczu.edu.cn.
authors.forename: Yading
authors.initials: Y
authors.lastname: Hou
authors.affiliation: Jiangsu Key Laboratory of Advanced Catalytic Materials & Technology, School of Petrochemical Engineering, Changzhou University, 1 Gehu Road, Changzhou 213164, China. txf@cczu.edu.cn.
authors.forename: Xiaofeng
authors.identifier: http://orcid.org/0000-0002-6789-1691
authors.initials: X
authors.lastname: Tong