Improved Method for the Synthesis of β-Carbonyl Silyl-1,3-Dithianes by the Double Conjugate Addition of 1,3-Dithiol to Propargylic Carbonyl Compounds
摘要:
Base-mediated double Conjugate addition of 1,3-propane dithiol to various silylated propargylic aldehydes and ketones allows for an efficient and scalable synthesis of beta-carbonyl silyl-1,3-dithianes.
method of silyl dienol ethers via 1,4-Brook rearrangement–Wittig reaction sequence has been developed. This tandem reaction proceeded via the intramolecular silyl migration step, which enabled stereoselective formation of phosphorane intermediates. The reaction is operationally simple and high yielding, thus providing a new useful formula for silyl dienol ether synthesis.
The cobalt-catalyzed carboxylation of propargyl acetates with CO2 (1 atm) is described. The reaction proceeds at room temperature in the presence of Mn powder as a reducing reagent. Various propargyl acetates are converted to the corresponding carboxylic acids in good to high yields.
Developing asymmetric iron and ruthenium-based cyclone complexes; complex factors influence the asymmetric induction in the transfer hydrogenation of ketones
作者:Jonathan P. Hopewell、José E. D. Martins、Tarn C. Johnson、Jamie Godfrey、Martin Wills
DOI:10.1039/c1ob06010d
日期:——
The preparation of a range of asymmetric iron and ruthenium-cyclone complexes, and their application to the asymmetric reduction of a ketone, are described. The enantioselectivity of ketone reduction is influenced by a single chiral centre in the catalyst, as well as by the planar chirality in the catalyst. This represents the first example of asymmetric ketone reduction using an iron cyclone catalyst.
Asymmetric cyanosilylation of alkynyl ketones with the catalyst systems consisting of amino acid/2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl (BINAP)/ruthenium(II) complex and lithium phenoxide (Ru⋅Li cat.) was studied. The reaction was conducted in tert‐butyl methyl ether (TBME) at −78 °C with a substrate‐to‐catalyst molar ratio (S/C) as high as 2000. A series of simple and functionalized ketones was converted
Synthesis of (Arylalkenyl)silanes by Palladium-Catalyzed Regiospecific and Stereoselective Allyl Transfer from Silyl-Substituted Homoallyl Alcohols to Aryl Halides
The reactions of silyl-substituted homoallyl alcohols with arylhalides under palladium catalysis result in regiospecific and stereoselective allyl transfer from the alcohols to arylhalides, offering modular synthesis of (E)-3-aryl-1-alkenyl-, (E)-1-aryl-2-alkenyl-, and optically active (E)-1-aryl-2-butenylsilanes.