Oxidatively generated electrophiles as initiators of epoxide cascade cyclization processes
摘要:
Oxidatively generated oxocarbenium ions are shown to be effective promoters of polyepoxide cascade cyclization reactions to form polyether compounds. The reaction conditions are neutral, ensuring that background acid-mediated processes are not operative and that other acid-sensitive functional groups, such as acetals, can be incorporated into cyclization substrates. While 5-exo pathways are more common that 6-endo pathways, a rational design has been employed to access tetrahydropyranyl ethers. (c) 2005 Elsevier Ltd. All rights reserved.
Electron Transfer Initiated Heterogenerative Cascade Cyclizations: Polyether Synthesis under Nonacidic Conditions
作者:V. Satish Kumar、Danielle L. Aubele、Paul E. Floreancig
DOI:10.1021/ol0261074
日期:2002.7.1
been employed to initiate heterogenerative cascade cyclization reactions that form polyether compounds under essentially neutral conditions. The reactions proceed through mesolytic benzylic carbon-carbonbond cleavages of homobenzylic ether-derived radical cations followed by intramolecular epoxonium ionformation, leading to further cyclizations. Both oligotetrahydrofuran and tetrahydropyran structures