Alkenes continued hydroboration

Studies relating to the stereoselective hydroboration of polyfunctional alkenes continue to appear. Various vinyl substituted pyridines, thiophenes and furans have been reacted with representative hydroborating agents,11" and further aspects of the hydroboration of cyclic dienes have been disclosed.11 The asymmetric hydroboration of cyclic enol ethers and enamines (heterocyclic alkenes) provides access... 

In total, over the past six years, the chelating P,N-ligands have shown considerable promise in a variety of enantioselective processes, including transfer-hydrogenation and hydrosilylation of ketones, hydroboration of alkenes, conjugate addition to enones and Lewis-acid catalysed Diels-Alder reactions, in addition to those described above.128,341 It is anticipated that this list will continue to grow, and... 

Brown and co-workers have continued their extensive studies of the mechanisms of hydroboration. Some of this work has recently been reviewed. Kinetic studies have been reported of the reaction of 9-borabicyclo[3.3.1]nonane dimer (3) with alkenes, alkynes, aldehydes, and ketones, in various solvents and with various Lewis bases and Br0nsted acids. Earlier studies suggested that the reaction of (3) with alkenes in a variety of solvents proceeded via the initial dissociation as in equation (4) to the monomer (4) followed by the hydro-... 

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