Propellanes 4.2.1 Propellene

We tried in 1968, as it turned out, unsuccessfully, to prepare a propellane having the [4.2.2] nucleus (actually it was a [4.2.2]propellene). But we were most successful in preparing the isomeric dispiran 7. None of the desired propellane was formed (see reaction scheme) ... 

Further, a very recent paper has reported a cascade rearrangement, under acidic conditions of the simpler educt, a dispiro[3.0.3.3]undecane derivative 93 to the dehydrated isomeric propellane 94 40). It is somewhat reminiscent of the analogous case of 26 where silver ion is the catalyst10). Treatment of the dispiro-alcohol 78 when heated for 2 hrs at 70 °C with p-toluenesulfonic acid in benzene gives in quantitative yield the [3.3.3]propellene 94. The following cascade is proposed to explain the rearrangement. 

In contrast to the [5.3.1]propellanes, reaction of chloro[4.3.1]propellene 33 or dihalo[4.3.1]propellane 34 with t-BuOK yielded Dewar benzene isomer 35 of... 

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See also in sourсe #XX -- [ ]

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