Aluminum Hydrides Stabilized by N‐Heterocyclic Imines as Catalysts for Hydroborations with Pinacolborane. Issue 22 (3rd November 2016)

• Record Type: Journal Article
• Authors: Franz, Daniel; Sirtl, Lorenz; Pöthig, Alexander; Inoue, Shigeyoshi
• Other Names: Inoue S. guestEditor.; Rivard E. guestEditor.
• Is Part Of: Zeitschrift für anorganische und allgemeine Chemie. Volume 642:Issue 22(2016)
• Page Start: 1245
• Page End: 1250
• Publication Date: 2016-11-03
• Subjects: Homogenous catalysis; Aluminum; Hydrides; Hydrogen transfer; Reduction; Chemistry, Inorganic -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1002/zaac.201600313
• Languages: English
• ISSNs: 0044-2313

Abstract

Abstract : The catalytic activity of the NHI‐substituted aluminum hydrides {L Mes NAlH2 }2 (1a ), {L Dip NAlH2 }2 (1b ), {L Mes NAl(H)OTf}2 (2a ), and {L Dip NAl(H)OTf}2 (2b ) in the hydroboration of terminal alkynes (for1 ), as well as carbonyl compounds (for2 ) with pinacolborane (4, 4, 5, 5‐tetramethyl‐1, 3, 2‐dioxaborolane) is investigated (L Mes N = 1, 3‐dimesityl‐imidazolin‐2‐imino, Mes = 2, 4, 6‐trimethylphenyl, L Dip N = 1, 3‐bis(2, 6‐diisopropylphenyl)‐imidazolin‐2‐imino, Tf = triflyl). With the implementation of1 as a catalyst, the hydroboration of selected terminal arylalkynes requires elevated temperature (80 °C) to proceed. The less sterically congested1a produces faster conversions than the bulkier1b . With the use of2 as a catalyst, the hydroboration of carbonyl compounds occurs at room temperature. An increased steric hindrance of the catalyst (2a vs.2b ) does not mitigate the rate of conversion to a relevant degree. Abstract :