STEREOSELECTIVE SULFUR EXTRUSION REACTION OF SYN-10,20-DIBROMO-2,3,12,13-TETRATHIA[4.4]METACYCLOPHANES AND ANTI-10,20-DIBROMO-2,3,12,13-TETRATHIA[4.4]METACYCLOPHANES TO THE CORRESPONDING SYN-DITHIA[3.3]METACYCLOPHANES AND ANTI-DITHIA[3.3]METACYCLOPHANES

A new cyclophane, 10,20-dibromo-2,3,12,13-tetra-thia[4.4]metacyclophane (1), has been synthesized by the oxidative coupling reaction of 2,6-bis(mercaptomethyl)-1-bromobenzene with I2. Both syn and anti isomers of 1 can be isolated at room temperature. The thermal sulfur extrusion reaction of anti-1 with (Et2N)3P afforded anti-9,18-dibromo-2,11-dithia[3.3]metacyclophane, while syn-1 gave 9,19-dibromo-2,11,12-trithia[3.4]metacyclophane. syn-9,18-Dibromo-2,11-dithia[3.3]metacyclophane was produced from the photochemical sulfur extrusion of syn-1 with (MeO)3P.