Nickel/(S)-t-Bu-PHOX complexcatalyzedasymmetric arylative cyclization of N-alkynones has been achieved, delivering 1,2,3,6-tetrahydropyridines containing a chiral tertiary alcohol in high yields and excellent enantioselectivities, which provides efficient access to chiral tetrahydropyridine and piperidine analogues.
已实现镍/( S )- t -Bu-PHOX 复合物催化N -炔酮的不对称芳基化环化,以高产率和优异的对映选择性提供含有手性叔醇的 1,2,3,6-四氢吡啶,从而提供有效的获取手性四氢吡啶和哌啶类似物。
reactions involving nickel‐catalyzed additions of (hetero)arylboronic acids to alkynes, followed by cyclization of the alkenylnickel intermediates onto tethered acyclic ketones to give chiral tertiary‐alcohol‐containing products in high enantioselectivities, are described. The reversible E/Z isomerization of the alkenylnickel intermediates enables overall anti‐arylmetallative cyclization to occur. The ring
Visible-light induced metal-free intramolecular reductive cyclisations of ketones with alkynes and allenes
作者:Nana Tang、Raphael J. Zachmann、Hui Xie、Jun Zheng、Bernhard Breit
DOI:10.1039/d2cc06972e
日期:——
visible-light-induced, intramolecular, reductive cyclisation of ketones with an unsaturated hydrocarbon moiety was developed. In contrast to conventional protocols requiring resource precious or hazardous metal sources, this method enables facile access to ketyl radicals under metal-free and mild reaction conditions. By polarity-reversed, ketyl radical hydroalkoxylation of alkynes and allenes, a variety of
Silver(I)‐Catalyzed Conia‐Ene Reaction: Synthesis of 3‐Pyrrolines
<i>via</i>
a 5‐
<i>endo</i>
‐
<i>dig</i>
Cyclization
作者:Siva Senthil Kumar Boominathan、Wan‐Ping Hu、Gopal Chandru Senadi、Jeh‐Jeng Wang
DOI:10.1002/adsc.201300844
日期:2013.12.16
AbstractA novel method has been developed for the synthesis of 3‐pyrrolines from β‐ketopropargylamines via a 5‐endo‐dig carbocyclization. This transformation involves a silver‐catalyzed Conia‐ene type reaction tolerating broad substrate scope with good to excellent yields. Furthermore, this methodology has been extended for the construction of 2‐substituted pyrroles under base‐mediated conditions.magnified image