Dec 12, 2017

Stereoselective Transfer Semi-Hydrogenation of Alkynes to E-Olefins with N-Heterocyclic Silylene-Manganese Catalysts

Chemistry : a European Journal
Yu-Peng ZhouMatthias Driess

Abstract

The synthesis and structures of the first SiII -donor supported manganese(II) complexes [L1]MnCl2 , [L2]MnCl2 , and [L3]2 MnCl2 are reported, bearing a pincer-type bis(NHSi)-pyridine ligand L1, bidentate bis(NHSi)-ferrocene ligand L2, and two monodentate NHSi ligands L3 (NHSi = N-heterocyclic silylene), respectively. They act as unprecedented very active and stereoselective Mn-based precatalysts (1 mol % loading) in transfer semi-hydrogenations of alkynes to give the corresponding E-olefins using ammonia-borane as a convenient hydrogen source under mild reaction conditions. Complex [L1]MnCl2 shows the best catalytic performance with quantitative conversion rates and excellent E-stereoselectivities (up to 98 %) for different alkyne substrates. Different types of functional groups can be tolerated, except CN, NH2 , NO2 , and OH groups at the phenyl group of 1-phenyl substituted alkynes.

Mentioned in this Paper

Manganese
Pyridines
Amines
Phenyl
TCEB1 gene
Complex (molecular entity)
Hydrogen Measurement
Manganese chloride
BAG3
TCEB3 gene

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