322429-80-1Relevant articles and documents
A Lewis Base Nucleofugality Parameter, NFB, and Its Application in an Analysis of MIDA-Boronate Hydrolysis Kinetics
Taylor, Nicholas P.,Gonzalez, Jorge A.,Nichol, Gary S.,García-Domínguez, Andrés,Leach, Andrew G.,Lloyd-Jones, Guy C.
supporting information, p. 721 - 729 (2022/01/04)
The kinetics of quinuclidine displacement of BH3 from a wide range of Lewis base borane adducts have been measured. Parameterization of these rates has enabled the development of a nucleofugality scale (NFB), shown to quantify and predict the leaving group ability of a range of other Lewis bases. Additivity observed across a number of series R′3-nRnX (X = P, N; R′ = aryl, alkyl) has allowed the formulation of related substituent parameters (nfPB, nfAB), providing a means of calculating NFB values for a range of Lewis bases that extends far beyond those experimentally derived. The utility of the nucleofugality parameter is explored by the correlation of the substituent parameter nfPB with the hydrolyses rates of a series of alkyl and aryl MIDA boronates under neutral conditions. This has allowed the identification of MIDA boronates with heteroatoms proximal to the reacting center, showing unusual kinetic lability or stability to hydrolysis.
A novel type of chiral triangulane-based diphosphane ligands for transition metals
Khlebnikov, Alexander F.,Kozhushkov, Sergei I.,Yufit, Dmitry S.,Schill, Heiko,Reggelin, Michael,Spohr, Volker,De Meijere, Armin
experimental part, p. 1530 - 1545 (2012/05/04)
A new original strategy for the synthesis of axially and helically chiral bidentate diphosphane ligands featuring a rigid triangulanyl backbone has been elaborated and executed for several representative enantiomerically pure ligands. Thus,(1R,3S,4S)-1,4-bis[(diphenylphosphanyl)methyl]spiro[2.2]pentane [(1R,3S,4S)-24·(BH3)2], [(1R,3R,4S)-4- (diphenylphosphanyl)methylspiro[2.2]pentan-1-yl]diphenylphosphane [(1R,3R,4S)-27·(BH3)2], [(1R,3R,4S,5R)-5- (diphenylphosphanyl)methyldispiro[2.0.2.1]heptan-1-yl]diphenylphosphane [(1R,3R,4S,5R)-30·(BH3)2], (1S,3S,4S)-1,4- bis(diphenylphosphanyl)spiropentane [(1R,3S,4S)-35·(BH3) 2], (1S,3S,4S)-1,4-bis(diphenylphosphanyl)spiropentane [(1S,3S,4S)-35·(BH3)2], (1S,3S,4S)-1,4- bis(diphenylphosphanyl)spiropentane [(1R,3R,4S)-35·(BH3) 2], and (1R,3R,4R,5R)-1,5-bis(diphenylphosphanyl)dispiro[2.0.2.1] heptane [(1R,3R,4R,5R)-36·(BH3)2] with a spiropentyl and a dispiro[2.0.2.1]heptyl moiety, respectively, have been prepared as bishydroborane complexes applying repetitively the same set of standard synthetic operations, starting from [(1S,3R)-4-methylenespiropent-1-yl] methyl acetate [(1S,3R)-7], (4,4-dibromospiropent-1-yl)methanols [(1S,3R)-8 and (1R,3S)-8] and (dibromodispiro[2.0.2.1]heptyl)methanols (1R,3S,4R)-9, (1S,3R,4S)-9 and (1S,3R,4R)-9 in 4-7 steps. The relative configurations of all important intermediates as well as the absolute configurations of the key intermediates and most final products were established by X-ray crystal structure analyses.
