Cu-Catalyzed Cyclization/Coupling of Alkenyl Aldimines. Indolization of Aldehydes, Anilines and Arylzinc Reagents

Abstract

We report a Cu(II)-catalyzed cyclization/coupling of alkenyl aldimines with arylzinc reagents to create complex indole-3-diarylmethane derivatives. The aldimines are readily available by simple dehydration, making the process a formal three-component reaction that strategically combines alkenyl aldehydes, anilines and arylzinc reagents to generate substituted indole-3-diarylmethane cores. Since the cyclization/coupling of alkenyl aldimines is unknown to date, the current method discloses an uncharted chemical space with regard to both the substrate and product diversity for this class of reaction.

Cu-Catalyzed Cyclization/Coupling of Alkenyl Aldimines with Arylzinc Reagents: Access to Indole-3-diarylmethanes

“…Transition metal-catalyzed cyclization/coupling of alkenyl halocarbons with carbon sources is a promising synthetic method to generate complex carbocycles and heterocycles rapidly from simple chemicals. , Since early disclosures, a number of catalytic systems have been developed that exploited ortho - N / O -allyl­(2-methyl)­iodoarenes (Scheme , 1a ) as alkenyl haloarenes, and organotin and organoboron reagents as coupling partners. These Pd-catalyzed reactions involved alkyl-Pd­(II) intermediates lacking β-Hs.…”