Rhodium catalysed dehydrogenative borylation of vinylarenes and 1,1-disubstituted alkenes without sacrificial hydrogenation--a route to 1,1-disubstituted vinylboronates

The complex trans-[Rh(Cl)(CO)(PPh3)2] (1) is an efficient catalyst precursor for the dehydrogenative borylation of alkenes without consumption of half the alkene substrate by hydrogenation, giving useful vinylboronate esters including 1,1-disubstituted derviatives that cannot be made by alkyne hydroboration.     

Generalized Weighted Morrey Estimates for Marcinkiewicz Integrals with Rough Kernel Associated with Schrödinger Operator and Their Commutators

Let L =-?+V(x) be a Schr?dinger operator, where ? is the Laplacian on ■~n,while nonnegative potential V(x) belonging to the reverse H?lder class. The aim of this paper is to give generalized weighted Morrey estimates for the boundedness of Marcinkiewicz integrals with rough kernel associated with Schr?dinger operator and their commutators.Moreover, the boundedness of the commutator operators formed by BMO functions and Marcinkiewicz integrals with rough kernel associated with Schr?dinger operators is discussed on the generalized weighted Morrey spaces. As its special cases, the corresponding results of Marcinkiewicz integrals with rough kernel associated with Schr?dinger operator and their commutators have been deduced, respectively. Also, Marcinkiewicz integral operators, rough Hardy-Littlewood(H-L for short) maximal operators, Bochner-Riesz means and parametric Marcinkiewicz integral operators which satisfy the conditions of our main results can be considered as some examples.     

Synthesis, characterisation and molecular structure of [Rh(COE)2(acac)] (COE=cyclooctene, η-C8H14), an important starting material for the preparation of rhodium catalyst precursors

The compound [Rh(COE)₂(acac)] (1) is a catalyst precursor in its own right, and a starting material for the preparation of other catalyst precursors for use in a variety of reactions such as hydroboration, diboration and the addition of arylboronic acids to aldehydes. Although a preparation using Tl(acac) and [Rh(COE)₂(μ-Cl)]₂ is in the literature, it would appear that it is not widely known and we have received several requests for our synthetic protocol for 1, which does not use any thallium salts. We present herein a synthesis of 1 from [Rh(COE)₂(μ-Cl)]₂ and Na(acac), along with its full spectroscopic and structural characterisation. The single crystal X-ray structure of 1 indicates approximate square-planar geometry at Rh, with the two olefinic CC bonds lying perpendicular to the square plane.