A method for the expeditious assembly of a diverse range of biaryl-bridged 8–11 membered N-heterocycles that relies on gold(I)-catalyzed intramolecular [4 + 2] benzannulation of N-tethered diynyl benzaldehydes is described.
An asymmetric Michael–alkylation reaction with a reversal of enantioselectivity catalyzed by chiral cobalt complexes is reported, giving spiro-cyclopropane-oxindoles with a complete and controlled switch in stereoselectivity (up to 99% and −98% ee).
A diacceptor diazo derivative undergoes a facile annulation with indoles promoted by a strong Brønsted acid to form tetrahydrocarbazoles.
A new copper(II)-catalyzed reaction of α-carbonyl-γ-alkynyl sulfoxonium ylides with sulfonyl hydrazides in the presence of tert-butyl hydroperoxide (TBHP) is reported, regio- and stereoselectively accessing (1Z,3Z)-1,3-bismethyleneisobenzofurans.
Cobalt-catalyzed Pauson–Khand reaction enables the synthesis of π-extended tetrahydrocyclopentaquinolinones with strong fluorescence. DFT studies reveal structure–property relationships for potential optoelectronic applications.