Cobalt-Catalyzed Carbonylative Cross-Coupling of Alkyl Tosylates and Dienes: Stereospecific Synthesis of Dienones at Low Pressure
作者:Brendon T. Sargent、Erik J. Alexanian
DOI:10.1021/jacs.7b07983
日期:2017.9.13
carbonylative coupling of alkyl tosylates and dienes producing enantioenriched dienones. This catalytic process proceeds under low pressure and mild conditions using a simple cobalt catalyst and extends to diverse tosylate and diene coupling partners. The transformation constitutes a unique, convergent approach to the asymmetric synthesis of valuable carbonyl compounds from easily accessed starting materials
Tosylation of some alcohols and phenols has been directly carried out with p-toluenesulfonyl chloride using heterodoxy acids (H3PW12O40, H3PMo12O40, AlPW12O40, and AlPMo12O40) as catalysts in the absence of solvent. We found that heteropoly acids AlPW12O40 and AlPMo12O40 were effective catalysts for the tosylation of alcohols and phenols. In the case of aliphatic alcohols, secondary alcohols undergo
Industrial process for the efficient production of aniline derivatives which are important intermediates for the manufacture of oxazolidinedione derivatives and tetrahydrophthalimide derivatives which are useful as active ingredients of herbicides. The process starts from 2,4-dihalo-5-aminophenol or bis(2,4-dihalo-5-aminophenyl)carbonate and selectively cycloalkylates or alkynylates the hydroxy group without protecting the amino group, whereby aniline derivatives having the cycloalkyloxy group or alkynyloxy group can be produced in high yield.
An Expedient Synthesis of Dialkylphosphane-Borane Complexes from Sodium Phosphide, and Their Alkylation under Phase-Transfer Conditions
作者:Peter Kasák、Michael Widhalm
DOI:10.1055/s-2007-990777
日期:2007.10
A group of seven achiral, α- and β-chiral dialkylphosphanes were synthesized in one step from sodium phosphide and alkyl sulfonates or sulfates. The corresponding borane complexes were further alkylated with alkyl, allyl, and benzyl bromides and mesylates to give tertiary mono- and diphosphanes, either via lithium phosphide-borane complexes at low temperature (45-78%) or under phase-transfer conditions (79-91%).
The present invention relates to a method for preparing di-α-chiral and achiral di(sec. alkyl)phosphines of general formula Ia or Ib
which is characterized in that sulfonates of general formula IIa or IIc or sulfates of general formula IIb or IId, are reacted with M3P, wherein M is selected from Li, Na, K, and mixtures thereof, preferably Na.
The secondary phosphines obtained are useful precursors for the preparation of tertiary phosphines and diphosphines.