Vinyloxiranes thermal rearrangement

Heterocyclic variants of VCP-CP rearrangement have also been explored to synthesize five-membered heterocyclic rings, although to a lesser extent than their carbocyclic counterparts. The ring expansion of vinylaziridines to pyrroline products was reported independendy by Atkinson and Rees in 1967 and by Lwowski and coworkers in 1968, whereas the corresponding thermal rearrangement of vinyloxiranes to dihydrofurans was disclosed by Paladini and Chuche in 1971 fScheme 11.231. ... 

The analogous vinyloxirane-dihydrofuran rearrangement has also been developed. Hudliclq et al. reported the thermal deconposition of vinyloxiranes, which were prepared by low-temperature addition of the lithium dienolate of ethyl-2-bromocrotonate to aldehydes. Subsequent pyrolytic rearrangement afforded the corresponding 2,3-dihydroftirans in variable yields fScheme 11.261. ... 

Scheme 11.27 Thermal rearrangement of chiral aimliary-bound vinyloxirane.

In the thermally-induced rearrangement of 2-vinyloxirane (Eq. 382), dihydro-furan is formed by thermolysis of the oxirane C-C bond via an ylide intermediate. 

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