Alkali Metal–Promoted Facile Synthesis of Secondary Amines from Imines and Carbodiimides. (18th May 2020)

• Record Type: Journal Article
• Authors: Panda, Tarun K.; Banerjee, Indrani; Sagar, Shweta
• Is Part Of: Applied organometallic chemistry. Volume 34:Number 9(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-05-18
• Subjects: Aldimines and carbodiimides -- alkali metal alkyl -- Chemoselectivity -- hydroboration; Organometallic chemistry -- Periodicals; Organometallic compounds -- Periodicals; 547.05
• DOI: 10.1002/aoc.5765
• Languages: English
• ISSNs: 0268-2605

Abstract

Abstract: We present here an efficient method for the hydroboration of aldimines (‐C=N‐) with pinacolborane (HBpin) using an alkali metal catalyst, potassium benzyl. The reaction was accomplished with unprecedented catalytic efficiency under mild and solvent‐free conditions to afford the high yield of the corresponding N‐boryl amines up to 97%. Various functionalities on aldimines were incorporated for hydroboration. The corresponding boryl amines were subjected to further hydrolysis to yield the corresponding secondary amines with good yields up to 89%. This protocol for the reaction demonstrates an atom‐economic and green method with diverse imines that bears excellent functional group tolerance. Chemoselective reduction of imines was also attained, with good yields of 74–89%. We also propose the most plausible mechanism involving the formation of metal hydride as the active pre‐catalyst. Abstract : Catalytic hydroboration of imines and carbodiimdes with pinacolborane (HBpin) using the potassium alkyl complex (KCH2 Ph) under mild and solvent‐free conditions to afford corresponding secondary amines and formimidamides in high yield is reported.