title: Transition-Metal-Free TBAI-Facilitated Addition-Cyclization of N-Methyl-N-arylacrylamides with Arylaldehydes or Benzenesulfonohydrazides: Access to Carbonyl- and Sulfone-Containing N-Methyloxindoles.
abstract: A highly efficient addition-cyclization of N-methyl-N-arylacrylamides with arylaldehydes or benzenesulfonohydrazides was developed using a catalytic amount of the quaternary ammonium salt (TBAI) under metal-free conditions, leading to the carbonyl- and sulfone-containing oxindoles. Compared to previous methods, which require excessive amounts of explosive organic peroxides and precious or toxic metal reagents, the present protocol, which gave access to 3,3-disubstituted oxindoles, is a safe and green approach, resulting in the formation of various useful carbonyl- and sulfone-containing oxindoles in yields of 40-94%.
authors.affiliation: College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University , Changsha 410082, China.
authors.forename: Peng-Yi
authors.initials: PY
authors.lastname: Ji
authors.affiliation: College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University , Changsha 410082, China.
authors.forename: Ming-Zhong
authors.initials: MZ
authors.lastname: Zhang
authors.affiliation: College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University , Changsha 410082, China.
authors.forename: Jing-Wen
authors.initials: JW
authors.lastname: Xu
authors.affiliation: College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University , Changsha 410082, China.
authors.forename: Yu-Feng
authors.initials: YF
authors.lastname: Liu
authors.affiliation: College of Chemistry and Chemical Engineering, Advanced Catalytic Engineering Research Center of the Ministry of Education, Hunan University , Changsha 410082, China.
authors.forename: Can-Cheng
authors.initials: CC
authors.lastname: Guo