Röntgenstrukturanalyse des dimeren 2,2‐Diphenylcyclopropanthiocarbonsäure‐ S‐tert ‐butylester‐Lithium‐Enolat · TMEDA‐Komplexes: ein „ganz normales”︁ Ester‐Enolat und ein „ganz normales”︁ Methylencyclopropan‐Derivat

X‐ray Crystal Structure of the Dimeric tert‐Butyl 2,2‐Diphenylcyclopropanecarbothioate Lithium Enolate · TMEDA Complex: an “Ordinary” Ester Enolate Containing an “Ordinary” Methylenecyclopropane Moiety After many unsuccessful attempts we now succeded in growing a suitable crystal of a cyclopropanecarbothioate lithium enolate (title compound 11c ) for X‐ray crystal structure analysis. 11c crystallizes as a tetramethylethylenediamine (TMEDA) complex in large cubes and contains hexane, is unstable above − 20°C and twinned. 11c is not C‐lithiated, but exhibits features normal for an ester lithium enolate: a double bond with planar trigonal centers, a methylene cyclopropane moiety with bond lengths and angles almost identical with those in corresponding hydrocarbons, a dimeric aggregation with an almost planar Li‐O‐Li‐O ring, with the large hydrocarbon units in a cis arrangement (Figure 1,2). A comparison with other lithiated cyclopropanes is made (Figure 3). The X‐ray crystal structure analysis shows 11c to form a channel structure in which n ‐hexane is included. The structure described here is the first one of a thiocarboxylic acid S ‐ester lithium enolate.