Reactions of sterically congested 1,6‐ and 1,7‐bis(diazo)alkanes with elemental sulfur and selenium: Formation of cyclohexene, 1,2‐dithiocane, 1,2‐diselenocane, and 1,2,3‐triselenecane derivatives

Abstract

AbstractThe reaction of 3,8‐bis(diazo)‐2,2,4,4,7,7,9,9‐octamethyldecane (5) with elemental selenium in 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) at 130°C yielded 1,2‐di‐tert‐butyl‐3,3,6,6‐tetramethylcyclohexene (1) (64%) and trans‐3,8‐di‐tert‐butyl‐4,4,7,7‐tetramethyl‐1,2‐diselenocane (8) (13%), while that of 5 with elemental sulfur in DBU gave trans‐3, 8‐di‐tert‐butyl‐4,4,7,7‐tetramethyl‐1,2‐dithiocane (9) (77%). The reaction of 3,9‐bis(diazo)‐2,2,4,4,8,8,10,10‐octamethylundecane (6) with elemental selenium in DBU at 80°C gave a cyclic triselenide, cis‐4,10‐di‐tert‐butyl‐5,5,9,9‐tetramethyl‐1,2,3‐triselenecane (11), in 15% yield as the only identifiable product. The structures of 9 and 11 were confirmed by X‐ray crystallography. © 2002 Wiley Periodicals, Inc. Heteroatom Chem 13:351–356, 2002; Published online in Wiley Interscience (www.interscience.wiley.com). DOI 10.1002/hc.10046