ABSTRACT
A tandem benzyne C-C σ-bond insertion reaction and photo-Nazarov cyclization protocol was developed, leading to the formation of three C-C bonds at consecutive positions of a benzene ring with concomitant assembly of a 6-5-6 tricyclic ring system. When 3-silylbenzyne precursors were employed, a tandem process involving a benzyne C-C σ-bond insertion, a photo-Nazarov cyclization, and a 1,3-silyl group migration was observed, which could produce 1,2,3,5-tetrasubstituted benzenes.
ABSTRACT
An unprecedented aryne 1,2,3-trifunctionalization protocol from 2,6-bis(silyl)aryl triflates was developed under transition-metal-free conditions. The reaction of generated 3-silylaryne with both pyridine N-oxide and N-hydroxylamide afforded o-silyl triflate/tosylate in a one-pot transformation, allowing the formation of 2,3-aryne precursors with various vicinal pyridinyl/amido substituents. These pyridinyl-substituted 2,3-aryne intermediates exhibit a broad scope of reactivity with diverse arynophiles in good yields and high selectivity.