Studies in group iv organometallic chemistry XXXIII. Heterocyclic tin compounds. The synthesis of 10,10-dimethylphenoxastannin, 10,10-diethylphenoxastannin and 10,10-dimethylphenothiastannin. The characterization of a new twelve-membered organotin heterocycle, C28H28O2Sn2

10,10-Dimethyl- and 10,10-diethylphenoxastannin have been prepared for the first time by the reaction of oxy-2,2′-bis (phenyllithium) with dimethyl- and diethyltin dichloride, respectively. The compound thought by Kupchik et al. to be dimeric 10,10-dimethylphenoxastannin has been found to be a twelve-membered organotin heterocycle, C28H28O2Sn2. PMR spectra in various solvents show this compound to be present in solution as an equilibrium mixture...