1,3-Di(methylthio)-2,2,4,4-tetramethylbicyclo[l.l.O]butane has been synthesized by two alternate routes and has been characterized by single crystal X-ray crystallography. This report corrects earlier, erroneous discussions of the title compound which have appeared in the literature. As part of our general studies of the properties of highly-strained polycyclic molecules> we recently desired a sample of 1,3-di(methylthio)-2,2,4,4-tetramethylbicyclo~l.l.O]butane (il. Although this compound had been previously described in the literature' and its preparation widely cited,3 the properties described for A' and the mechanistic details ascribed to its generation2 seemed suspect. Thus, we decided to prepare ,l, by an alternate route. Treatment of 2,2,4,4-tetramethylbicyclo[l.l.O]butane (2)" with a 30% excess of n-butyllithium and a 30% excess of tetramethylethylenediamine in hexane for 24 hours, followed by one equivalent of dimethyl disulfide gave a 61% yield of 2,2,4,4-tetramethyl-l-methylthiobicyclo-[l.l.O]butane (,$),5 bp 78" (24 mm). Repetition of this procedure on 2 gave a 2:l mixture of i and methylthiomethyl 2,2,4,4-tetramethylbicyclo[l.l.O]but-l-y1 sulfide (4).