title: Lithium Dihydropyridine Dehydrogenation Catalysis: A Group 1 Approach to the Cyclization of Diamine Boranes.
abstract: In reactions restricted previously to a ruthenium catalyst, a 1-lithium-2-alkyl-1,2-dihydropyridine complex is shown to be a competitive alternative dehydrogenation catalyst for the transformation of diamine boranes into cyclic 1,3,2-diazaborolidines, which can in turn be smoothly arylated in good yields. This study established the conditions and solvent dependence of the catalysis through NMR monitoring, with mechanistic insight provided by NMR (including DOSY) experiments and X-ray crystallographic studies of several model lithio intermediates.
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
authors.forename: Ross
authors.initials: R
authors.lastname: McLellan
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
authors.forename: Alan R
authors.identifier: 0000-0003-3652-6015
authors.initials: AR
authors.lastname: Kennedy
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
authors.forename: Samantha A
authors.initials: SA
authors.lastname: Orr
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
authors.forename: Stuart D
authors.identifier: 0000-0002-9330-8770
authors.initials: SD
authors.lastname: Robertson
authors.affiliation: WestCHEM, Department of Pure and Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK.
authors.forename: Robert E
authors.identifier: 0000-0002-1015-2564
authors.initials: RE
authors.lastname: Mulvey
keywords: cyclization; diaminoboranes; dihydropyridine; homogeneous catalysis; lithium