title: Synthesis of tertiary arylamines: Lewis acid-catalyzed direct reductive N-alkylation of secondary amines with ketones through an alternative pathway.
abstract: We report herein a highly efficient, tin(ii)/PMHS catalyzed reductive N-alkylation of arylamines with ketones affording tertiary arylamines. A very wide substrate scope was observed for the current catalytic method as all six permutations of ketones/aldehydes/heterocyclic carbonyls and primary/secondary/heterocyclic amines were well tolerated, enabling access to secondary, tertiary and heterocyclic amines. The method is also convenient for the synthesis of N-substituted isoindolinones and phthalazinones via a tandem amination-amidation sequence. Mechanistic investigations revealed a carbocationic pathway instead of an ordinary direct reductive amination pathway.
authors.affiliation: Natural Product Chemistry and Process Development Division, CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh 176 061, India. upendra@ihbt.res.in bikram_npp@rediffmail.com.
authors.forename: Onkar S
authors.initials: OS
authors.lastname: Nayal
authors.forename: Maheshwar S
authors.initials: MS
authors.lastname: Thakur
authors.forename: Vinod
authors.initials: V
authors.lastname: Bhatt
authors.forename: Manoranjan
authors.initials: M
authors.lastname: Kumar
authors.forename: Neeraj
authors.initials: N
authors.lastname: Kumar
authors.forename: Bikram
authors.initials: B
authors.lastname: Singh
authors.forename: Upendra
authors.initials: U
authors.lastname: Sharma
mesh_terms: D000478:Alkylation; D000588:Amines / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D007659:Ketones / Q000737:chemistry*; D058116:Lewis Acids / Q000737:chemistry*; D015394:Molecular Structure
chemical_list: D000588:Amines; D007659:Ketones; D058116:Lewis Acids