Abstract The reactions of 1, 2-dihydro-1-magnesabenzocyclobutene (5) with dichlorodimethylsilane (12a), dichlorodimethylgermane (12b) and dichlorodimethylstannane (12c) are reported; 1, 2-dihydro-1, 1, dimethyl-1-silabenzocyclobutene (14a) and 1, 2- dihydro-1, 1-dimethyl-1-germabenzocyclobutene (14b) were formed in high yields, but the tin analogue 14c was not obtained. Eight-membered ring species, the dimers 17 and 18, ...
