Silyl Phosphites. XVIII. Versatile Utility of α-(Trimethylsilyloxy)alkylphosphonates as Key Intermediates for Transformation of Aldehydes into Several Carbonyl Derivatives
作者:Mitsuo Sekine、Masashi Nakajima、Akiko Kume、Akio Hashizume、Tsujiaki Hata
DOI:10.1246/bcsj.55.224
日期:1982.1
trimethylsilyl phosphite (DTMSP) with aldehydes were converted, by treatment with lithium diisopropylamide (LDA) followed by the successive alkylation and alkalinehydrolysis, to carbonyl derivatives involving aldehydes, unsymmetrical ketones, β,γ-unsaturated ketones, and carboxylic acids. β-Substituted carboxylic esters and γ-substituted lactones were prepared by use of the carbonyl addition compounds of DTMSP
Ketones are prepared by reacting an aromatic or heterocyclic aldehyde in the presence of a cyanide ion with an unsaturated compound having the formula (I): ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 are the same or different and are selected from the group of hydrogen, optionally substituted aliphatic, cycloaliphatic, araliphatic, aromatic, heterocyclic and carboxylic acid ester and R.sup.4 is nitrile (CN), --CO--R.sup.5 or --CO--OR.sup.5 wherein R.sup.5 is selected from the group of optionally substituted aliphatic, cycloaliphatic, araliphatic, aromatic and heterocyclic and R.sup.1 and R.sup.2 and/or R.sup.1 and R.sup.3 and/or R.sup.2 and R.sup.5 or R.sup.3 and R.sup.5 together with the carbon atoms to which they are attached as substituents may also form a carbocyclic or heterocyclic ring. Ketones prepared according to the process of the invention have the formula: ##STR2## wherein R.sup.1 .sup.' and R.sup.3 .sup.' are identical or different and are selected from the group of hydrogen, lower alkyl having up to 3 C-atoms and optionally substituted phenyl; and R.sup.6 .sup.' is optionally substituted phenyl or a pyridyl.
Stereospecific Acylative Suzuki–Miyaura Cross-Coupling: General Access to Optically Active α-Aryl Carbonyl Compounds
作者:Byeongdo Roh、Abdikani Omar Farah、Beomsu Kim、Taisiia Feoktistova、Finn Moeller、Kyeong Do Kim、Paul Ha-Yeon Cheong、Hong Geun Lee
DOI:10.1021/jacs.3c00637
日期:——
stereospecific Pd-catalyzed acylative cross-coupling of enantiomerically enriched alkylboron compounds has been developed. The protocol features an extremely high level of enantiospecificity to allow facile access to synthetically challenging and valuable chiral ketones and carboxylic acid derivatives. The use of a sterically encumbered and electron-rich phosphine ligand proved to be crucial for the success
Photoredox-Catalyzed Radical–Radical Coupling of Potassium Trifluoroborates with Acyl Azoliums
作者:Michael J. Rourke、Matthew J. McGill、Karl A. Scheidt、Daniel Yang、Emelia J. Farnam、Joshua L. Zhu
DOI:10.1055/s-0041-1738448
日期:2023.11
partners in organic synthesis, particularly in the Suzuki–Miyaura coupling reaction. Recently, they have also been used as radical precursors under oxidative conditions to generate carbon-centered radicals. These versatile reagents have found new applications in photoredoxcatalysis, including radical substitution, conjugate-addition reactions, and transition-metal dual catalysis. In addition, this