Re(CO)5Br-Catalyzed Addition of Carboxylic Acids to Terminal Alkynes: A High Anti-Markovnikov and Recoverable Homogeneous Catalyst
摘要:
The addition of carboxylic acids to terminal alkynes is efficiently catalyzed by the early transition-metal complex Re(CO)(5)Br in toluene or n-heptane at 110 degreesC in an air atmosphere, affording the anti-Markovnikov adducts in good yields with high selectivity. In most cases, the reactions afford unusual Z-adduct predominantly. When n-heptane was used as solvent, Re(CO)(5)Br can be partly recovered from the reaction mixture.
Organic synthesis via magnetic attraction: benign and sustainable protocols using magnetic nanoferrites
作者:R. B. Nasir Baig、Rajender S. Varma
DOI:10.1039/c2gc36455g
日期:——
Magnetic nano-catalysts have been prepared using simple modification of iron ferrites. The nm size range of these particles facilitates the catalysis process, as an increased surface area is available for the reaction; the easy separation of the catalysts by an external magnet and their recovery and reuse are additional beneficial attributes. Glutathione bearing nano-ferrites have been used as organocatalysts for the Paal–Knorr reaction and homocoupling of boronic acids. Nanoferrites, post-synthetically modified by ligands, were used to immobilize nanometals (Cu, Pd, Ru, etc.) which enabled the development of efficient, sustainable and green procedures for azide–alkynes-cycloaddition (AAC) reactions, C–S coupling, O-allylation of phenol, Heck-type reactions and hydration of nitriles.
A facile, one-pot reductive alkylation of aromatic and heteroaromatic amines in aqueous micellar media: a chemoenzymatic approach
作者:Krithika Ganesh、Ganesh Sambasivam、Karthikeyan S
DOI:10.1039/d3ob00386h
日期:——
and practical method for the catalytic N-alkylation of amines using molecular hydrogen as the reductant was developed. This procedure involves a lipase-mediated one-pot chemoenzymatic cascade wherein an amine undergoes a reductive amination with an aldehyde generated in situ. The imine formed thereby is reduced to give the corresponding amine. This process represents a convenient, environmentally benign