Medium-sized cyclophanes. Part 46.1 The preparation and novel [3.3]- and [1.5]-sigmatropic rearrangements of [n.2]cyclophanes having a spiro skeleton †
- 1 January 1998
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society, Perkin Transactions 1
- No. 1,p. 123-130
- https://doi.org/10.1039/a704105e
Abstract
Oxidation of dihydroxy[n.2]metacyclophanes 4 with K3[Fe(CN)6] affords in good yield the intramolecular O–C coupling products 5 having a spiro skeleton. Variable temperature 1H NMR measurements indicate that compounds 5 are interconvertible by thermal [3.3]sigmatropic rearrangement. The free energies for the [3.3]sigmatropic rearrangement increase with increasing length of the methylene bridge in compounds 5. The substituent effect on the [1.5]sigmatropic rearrangement of [2.2]cyclophanes 3 having a spiro skeleton is also discussed.Keywords
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