Herein, we report carbene-mediated benzannulation of vinyl sulfoxonium ylides with electron-deficient alkynes and alkenes to synthesize oxygenated arenes. This protocol features excellent regioselectivity, a broad substrate scope, and mild reaction conditions. Mechanistic studies revealed that the reaction proceeds through furan generation, cycloaddition, ring cleavage, and aromatization cascades. The synthesized arenes have been utilized in diverse product transformations and arene ring homologation.

In this review, the coupling of two carbene precursors for the synthesis of alkenes is surveyed.The key to selective carbene coupling is the difference in the rate of carbene generation between the two carbene precursors. This strategy requires judicious selection between two carbene precursors as well as fine-tuning of reaction conditions to obtain the desired chemo-and stereoselectivity. These couplings were carried out in the presence and absence of a metal catalyst. The present review describes inter-and intramolecular coupling of diazo compounds and cross-coupling between diazo and non-diazo compounds. 1.Introduction 2.