Quest for Higher Ladderanes: Oligomerization of a Cyclobutadiene Derivative


  • This work was supported, in part, by the Council of Scientific and Industrial Research, New Delhi (Research Fellowships for MBV and GNS).


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Successive [4 + 2] cycloadditions of dimethyl 1,2-cyclobutadienedicarboxylate (1), first with itself and then with the next highest adducts 2 and 3, result in the [7]-ladderane 4. The [n]-ladderanes 24 are of interest because of their weak σ framework and the very different polarities of the two sides of the molecule. R = CO2Me.