Generation of hexahydroazulenes

(Z)-4,5-Dibromo-3,3,6,6-tetramethyl-2,3,6,7-tetrahydrothiepine-1,1-dione

“…As part of our studies on the reactivity of angle-strained compounds (Kra ¨mer et al, 2009;Detert 2011), the addition of bromine appeared to be a challenging project (Chiappe et al, 2002;Detert et al 1992). Whereas the addition of bromine to alkynes generally leads via bridged bromonium ions to trans-dibromoalkenes, the bromination of cyclooctyne gives cis-1,2-dibromocyclooctene (Wittig & Dorsch, 1968).…”

The head-to-head photodimer of indenoindene

“…Head-tohead and head-to-tail photodimers have been found in a 1: 2 ratio (Shim & Chae, 1982). As part of a project on strained (Detert et al, 2009;Dobryakov et al, 2016;Krohn et al, 2019) and polycyclic hydrocarbons (Krä mer et al, 2009;Detert & Meier, 1997a,b), indenoindene was prepared in a photochemical rearrangement of 1-(1-benzocyclobutenylidene)benzocyclobutene; concomitant 2 + 2-cycloaddition of indenoindene produced the title compound as a byproduct.…”