Darstellung und Komplexierung von 1,4‐Dimethyl‐2,3‐bis(isopropyliden)‐1,4‐diboratetralin

Synthesis and Complexation of 1,4‐Dimethyl‐2,3‐bis(isopropylidene)‐1,4‐diboratetraline 1,4‐Dimethyl‐2,3‐bis(isopropylidene)‐1,4‐diboratetraline ( 2 ) is obtained from o ‐dilithiumbenzene and 2,5‐dimethyl‐3,4‐bis(chloromethylboryl)‐2,4‐hexadiene in 61% yield. Its complexation with cyclopentadienylbis(ethene)cobalt leads to the triple‐decker bis(η 5 ‐cyclopentadienylcobalt)‐μ‐η 6 ,η 6 ‐1,4‐dimethyl‐2‐isopropenyl‐3‐isopropyl‐1,4‐dihydro‐1,4‐dibora‐naphthaline ( 3 ) in low yield. However, the reaction of 2 with (C 5 H 5 )Rh(C 2 H 4 ) 2 and (C 5 Me 5 )Co(C 2 H 4 ) 2 originates complexes of a tricyclic ligand formed from 2 via conrotatoric [2 + 2] cycloaddition of the isopropylidene groups. (η 5 ‐Cyclo‐pentadienylrhodium)‐η 6 ‐tricyclo‐[6.4.0.0 3,6 ]‐2,4,4,5,5,7‐hexamethyl‐2,7‐diboradodeca‐1,3,9,11‐tetraene ( 4 ), (η 5 ‐pentamethylcyclopentadienylcobalt)‐η 6 ‐tricyclo‐[6.4.0.0 3,6 ]‐2,4,4,5,5,7‐hexamethyl‐2,7‐diboradodeca‐1,3,9,11‐tetraene ( 5 ) and its related dinuclear complex 6 could be isolated in 29, 10, and 31%, respectively. Their constitutions are derived from spectroscopic data and proven by X‐ray structure analysis of 4 .