whereas the newly discovered disproportionation according to route B can be regarded as a hydrogenation of an azo double bond [4]. The structure (3) can be considered as a transition state, especially since diimide produced from benzenesulfonylhydrazide hydrogenates added tolane stereospecifically to gibe cis-stilbene in at least 95 "/, yield, according to infrared analysis.The consequences of this auto-hydio~eii:rtion ore currently being investigated. Received, February 13th. 1963 [Z 449/279 IE] [ I ] S. Hiinig and H.