Synthesis of ketones from iodoalkenes, carbon monoxide and 9-alkyl-9-borabicyclo[3.3.1]nonane derivatives via a radical cyclization and palladium-catalysed carbonylative cross-coupling sequence
Under irradiation (tungsten lamp), the palladium-catalysed three-component cross-coupling reaction between iodoalkenes such as 6-iodo-1-hexene or their derivatives, carbon monoxide (1 atm) and 9-alkyl- or 9-aryl-9-BBN derivatives (9-BBN = 9-borabicyclo[3.3.1]nonane) produces unsymmetrical ketones in moderate to high yields; the oxidative addition of iodoalkenes to a palladium(0) complex proceeds via a radical process, thus allowing cyclization of the iodoalkenes to five-membered rings prior to the couplings with carbon monoxide and boron reagents.
Stereoselective Synthesis of (<i>E</i>)-(Trisubstituted alkenyl)borinic Esters: Stereochemistry Reversed by Ligand in the Palladium-Catalyzed Reaction of Alkynylborates with Aryl Halides
The palladium-catalyzedreaction of alkynylborates with arylhalides stereoselectively gave (E)-(trisubstituted alkenyl)-9-BBNs, in which two different aryl groups were installed trans to each other.
Unexpected cluster formation upon hydroboration of a neutral diborene with 9-BBN
作者:Holger Braunschweig、Christian Hörl
DOI:10.1039/c4cc04476b
日期:——
The reaction of the neutral, base-stabilised diborenes 1a,b with the well-known hydroboration reagent 9-borabicyclo[3.3.1]nonane (9-BBN) is presented. This leads to the formation of a nonclassical structural motif with a B3 core concomitant with the cleavage of a B-C bond. This compound has been characterised in solution and by X-ray crystallography. According to Wade's rules these rare B3 clusters
A palladium-catalyzedannulation reaction of alkynylborates with o-iodophenyl ketones to form indenes is described. Highly substituted indeneskeletons are efficiently constructed with site-specific installation of the substituents.