Alkali metal complexes as efficient catalysts for hydroboration and cyanosilylation of carbonyl compounds. Issue 36 (25th July 2018)

• Record Type: Journal Article
• Authors: Harinath, Adimulam; Bhattacharjee, Jayeeta; Nayek, Hari Pada; Panda, Tarun K.
• Is Part Of: Dalton transactions. Volume 47:Issue 36(2018)
• Page Start: 12613
• Page End: 12622
• Publication Date: 2018-07-25
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt02032a
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Catalytic hydroboration of aldehydes and ketones with pinacolborane (HBpin) and catalytic cyanosilylation of carbonyl compounds with trimethylsilyl cyanide using alkali metal (Li, Na, K) complexes as precatalysts under mild conditions are reported. Abstract : We report here reactions between the N -adamantyliminopyrolyl ligand 2-(AdNCH)–C4 H3 NH (L–H ) and alkali metal hexamethyldisilazides [MN(SiMe3 )2 ] (M = Li, Na and K) to afford the dimeric [{2-(AdNCH)–C4 H3 NLi(THF)}2 ] (1 ), [{2-(AdNCH)–C4 H3 N}{Na(THF)1.5 }2 ] (2 ) and polymeric [{2-(AdNCH)–C4 H3 NK(THF)} n ] (3 ) complexes at ambient temperature. A one-pot reaction betweenL–H, [KN(SiMe3 )2 ] and alkaline earth metal diiodide (AeI2 ) in a 2 : 2 : 1 molar ratio, which resulted in the formation of a heteroleptic Ae metal complex [κ 2 -{2-(AdNCH)–C4 H3 N}2 Ae(THF)2 ] [Ae = Mg (4 ), Ca (5 )], is also reported. The solid-state structures of complexes1, 3 and4 were established through single-crystal X-ray diffraction analysis. The alkali and alkaline earth metal complexes1–5 were utilised as precatalysts for the catalytic hydroboration of pinacolborane (HBpin) with aldehydes and ketones, and potassium complex3 was identified as a competent catalyst under mild conditions. Additionally, cyanosilylation of carbonyl compounds was explored with trimethylsilyl cyanide and aldehydes/ketones, using the alkali metal precatalyst3 under mild conditions. In both catalytic processes, the potassium catalyst3 exhibited high tolerance towards a number of functional groups.