Rh-catalyzed chemo-, stereo- and regioselective C–H cascade annulation of indolyloxopropanenitriles for pyranoindoles
作者:Ramesh Kotipalli、Undamatla Suri Babu、Jagadeesh Babu Nanubolu、Maddi Sridhar Reddy
DOI:10.1039/d3cc02762g
日期:——
Selective annulations of alkynes represent a powerful tool for constructing multicyclic scaffolds while installing desired substitution patterns with precision. Herein, we report a Rh-catalyzed unique annulation of indolyl oxopropanenitrile with hydroxy-alkynoates to access pyranoindole cyclic motifs, featuring enol oxygen as a rare chemoselective reactive terminal. The reaction proceeds via a five-membered
Annulations of unsaturated systems through C–H activation represent a powerful tool for producing multicyclic scaffolds. Having coordinating centers in both annulation partners (a dual coordination strategy) would afford remarkable selectivities in the outcomes. Along this concept, we report herein a Pd-catalyzed regioselective rollover cascade dual C–H annulation of o-arylphenols with alkynols for
A regioselective rollover cyclometallation, assisted by conjugatedolefin, is unveiled for the annulation of alkynes at two distant C−H bonds of o-alkenyl phenols. The annulation follows a concomitant cyclization rewarding a rare triple C−H functionalization. The reaction is also totally regioselective with an array of unsymmetrical alkynes, taking the leverage of an extended conjugation or a tertiary
Electrophilic cyclization and concomitant C–Hannulation constitute an expedient cascade strategy for the construction of multicyclic scaffolds with precise substitutional patterns. We report here a novel Pd-catalyzed cyclative annulation of ynone oxime with activated alkynes. The cascade features a dual regioselectivity including site selective C–H activation and chelation-assisted selective insertion
Rh(iii)-catalyzed sequential spiroannulation/lactonization of 3-aryl N-sulfonyl ketimines with 4-hydroxy-2-alkynoates by C–H bond activation
作者:S. Prashanth、Chidrawar Ajay、Kommu Nagesh、B. Sridhar、B. V. Subba Reddy
DOI:10.1039/d3nj04312f
日期:——
been developed for the synthesis of a highly rigid spirobenzosultam lactones in good yields with high regioselectivity by means of aromatic ortho-C–H bondactivation/functionalization of 3-aryl N-sulfonyl ketimines with 4-hydroxy-2-alkynoates. The reaction proceeds through a cascade of C–H activation followed by spiroannulation and lactonization. In this approach, two C–C and C–O bonds are formed in a