Synthesis and Reactions of C4-Symmetric 1,3,5,7(1,3)-Tetrabenzenacyclooctaphane Tetraazide and Tetraamine Derivatives: Toward the Synthesis of Nitrogen-Embedded Zigzag Hydrocarbon Belts.

Starting from readily available tetratriflated resorcin[4]arene derivatives, C4-symmetric 1,3,5,7(1,3)-tetrabenzenacyclooctaphane tetraamines were synthesized conveniently by means of Pd-catalyzed C-N bond coupling reaction with diphenylmethanimine followed by hydrolysis. Subsequent Sandmeyer reaction and sulfonylation reaction efficiently afforded the corresponding tetraazide and tetrasulfonamide products, respectively. Upon treatment with PhI(OAc)2, tetrasulfonamides underwent facile oxidative transannular cyclization reaction to produce mono- and dispiro macrocyclic compounds selectively rather than N4-octahydrobelt[8]arenes. Conformational structures of resulting macrocycles are presented, and the reaction mechanism is discussed.