A new route to polyselenoether macrocycles. Catalytic macrocyclization of 3,3-dimethylselenatane by [Re2(CO)9

Abstract

3,3-Dimethylselenatane, SeCH 2 CMe 2 CH 2 , DMSe is cyclooligomerized catalytically at 115 °C in the presence of [Re 2 (CO) 9 (SeCH 2 CMe 2 C H 2 )] to yield three new polyselenoether macrocycles 3,3,7,7-tetramethyl-1,5-diselenacyclooctane, 3,3,7,7,11,11-hexamethyl-1,5,9-triselenacyclododecane, 3,3,7,7,11,11,15,15-octamethyl-1,5,9,13-tetra- selenacyclohexadecane and polymer of DMSe; all three macrocycles are characterized crystallographically; in all cases the gem-dimethyl groups are directed toward the exterior of the rings; interestingly, some methylene groups are directed to the interior.