的单釜,过渡金属-自由,多米诺迈克尔/ S Ñ普遍适用性的Ar协议已经通过使用硝基甲烷和设计用于多官能萘的区域选择性合成邻-haloaryl ynones。硝基甲烷作为一种碳碳负离子源的使用,并被引入到各种炔酮中,最终以芳族硝基取代基的形式出现。该多米诺法在多环生物碱马卡平的全合成中的应用证明了该方法的有效性。在概念上是简单的方法来影响ynones显示广泛的底物范围和官能团耐受性,并已与被取代的硝基甲烷实现的区域选择性,多功能benzoannulation以及与脂环ö-单倍体。
The metal-free oxidative alkene methylation/alkynylation of 1,4-enyn-3-ols with an organic peroxide as the methyl source has been developed, which provides straightforward and practical access to the challenging quaternary-carbon-containing but-3-yn-1-ones. The method is reasoned to go through methylation of functional alkenes utilizing dicumyl peroxide as the methylating reagent and subsequent intermolecular
Combining Electronic and Steric Effects To Generate Hindered Propargylic Alcohols in High Enantiomeric Excess
作者:Vijyesh K. Vyas、Richard C. Knighton、Bhalchandra M. Bhanage、Martin Wills
DOI:10.1021/acs.orglett.7b03884
日期:2018.2.16
o-fluoro substituents results in an improvement to the reduction enantioselectivity, as does the replacement of a phenyl ring on the alkyne with a trimethylsilyl group. These effects are rationalized as resulting from a change in the steric properties of the aryl ring and the electronic properties of the alkyne which, when matched in the reduction transition state, combine within a “window” of substrate/catalyst
the intermediates were isolated. A catalyst-free synthetic approach is described for the synthesis of 4-quinolone derivatives through a tandem amination/conjugated Michael addition sequence of 1-(2-fluorophenyl)prop-2-yn-1-one derivatives. The [5+1]-cyclization proceeds efficiently at a high temperature under an inert atmosphere with lithium carbonate as a base, and it provides a practicalroute to
Synthesis of 3-(2-quinolyl) chromones from ynones and quinoline <i>N</i>-oxides <i>via</i> tandem reactions under transition metal- and additive-free conditions
A novel method for the synthesis of 3-(2-quinolyl) chromones through a tandem [3+2] cycloaddition/ring-opening/O-arylation from ynones and quinoline N-oxides has been developed. This protocol proceeds under transition metal- and additive-free conditions and can be amplified to the gram level in 91% yield. 3-(1-Isoquinolyl) and 3-(2-pyridyl) chromones are also successfully synthesized using isoquinoline
Rh-catalyzed decarbonylation of conjugated ynones via carbon–alkyne bond activation: reaction scope and mechanistic exploration via DFT calculations
作者:Alpay Dermenci、Rachel E. Whittaker、Yang Gao、Faben A. Cruz、Zhi-Xiang Yu、Guangbin Dong
DOI:10.1039/c5sc00584a
日期:——
In this full article, detailed development of a catalytic decarbonylation of conjugated monoynones to synthesize disubstituted alkynes is described. The reaction scope and limitation has been thoroughly investigated, and a...