Synthesis of [3ⁿ]Cyclophanes and Related Compounds by Alkylation of Tosylmethyl Isocyanide with Bis (bromomethyl) benzenes

Abstract

Bis (2-isocyano-2-tosylethyl) benzenes (12a, 12b, and 12c), synthesized by the reaction of tosylmethyl isocyanide (7) with bis (bromomethyl) benzenes (11a, 11b, and 11c) in 2 : 1 molar ratio, reacted again with 11a, 11b, and 11c under phase-transfer conditions to form 2, 11-diisocyano-2, 11-ditosyl[3²]cyclophanes of ortho, meta, and para types (14, 15, and 17), 2, 11, 20-triisocyano-2, 11, 20-tritosyl[3³]paracyclophane (19), and 2, 11, 20, 29-tetratosyl[3⁴]cyclophanes of meta and para types (16 and 18). [3²]Metacyclophane (1), [3³]paracyclophane (31), and [3⁴]meta- and paracyclophanes (32 and 33) could be obtained by hydrolysis and Wolff-Kishner reduction of the above intermediates (15, 16, 18, and 19). Hydrolysis of 2, 11-diisocyano-2, 11-ditosyl[3²]orthocyclophane (14) yielded 5, 6, 11, 12-tetrahydro-dibenz[b, g]-azulen-5-one (30) instead of the corresponding ketone (26). Structural properties of the prepared cyclophanes (15, 17, 21, 23, 24, 31, and 33) are described on the basis of the proton magnetic resonance (PMR) spectra.