Fig. 5
From: Oxidative [4+2] annulation of styrenes with alkynes under external-oxidant-free conditions
Gram synthesis using sunlight source. Reaction conditions: the mixture of 1,1-diphenylethene 1a (13 mmol), 1-ethynyl-4-methoxybenzene 2a (10 mmol), Acr+-Mes ClO4− (1 mol%), Co(dmgH)2py2PF6 (3 mol%) in DCE (200 mL) was placed in a sunny place for 2 days; isolated yield was showed
