Journal article
Regioselective Nucleophilic Ring Opening of Epoxides and Aziridines derived from Homoallylic Alcohols
The regioselectivity of nucleophilic ring opening of some 3,4-epoxy and 3,4-aziridino alcohols has been studied. The nucleophiles chosen were complex hydrides (LiAlH4, Red-Al and DIBAL) and Lipshutz- or Gilman-type organocuprate reagents. The C-4 substituent in the substrates was varied in order to study steric and electronic effects on the ring opening reactions.
For alkyl substituents at C-4, most of the results can be explained on the basis of intramolecular delivery of the nucleophile to C-3 via a six-membered transition state, leading to 1,4-diols or 1,4-amino alcohol derivatives. In general, the epoxy alcohols gave poorer regioselectivity than the N-tosyl aziridino alcohols, for which selectivities of >95:5 were routinely obtained.
The activating effect of a phenyl group at C-4 led to a switch in regiochemistry, with the 1,3-diol or 1,3-amino alcohol derivative as the major product. (C) 1997 Elsevier Science Ltd.
Language: | English |
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Year: | 1997 |
Pages: | 16139-16146 |
ISSN: | 14645416 and 00404020 |
Types: | Journal article |
DOI: | 10.1016/S0040-4020(97)10053-9 |
ORCIDs: | Tanner, David Ackland |