Alkoxyl radical addition to acceptor-substituted carbon-carbon double bonds

作者：Kempter Irina; Gross Andreas; Hartung Jens^*

来源：Tetrahedron, 2012, 68(50): 10378-10390.

DOI：10.1016/j.tet.2012.08.083

• Acrylate
• Acrylonitrile
• Addition
• Alkoxyl radical
• Amino acid
• Bromo-cyclization
• Borderline reactivity
• Radicals
• Stereoselective synthesis
• Thiazolethione

Alkoxyl radicals add 5-exo-trig selectively to cyano- and methoxycarbonyl-substituted carbon carbon double bonds, to afford alpha-acceptor-alpha-tetrahydrofuryl-2-methyl radicals. Trapping of cyclized radicals by Bu3SnD furnishes products of site-specific deuterium-labeling in alpha-position to the acceptor group. In intramolecular competition experiments, alkoxyl radicals add similarly fast to a cyano-substituted double bond than to a terminal alkene, but by a factor %26gt;25 faster to an enol ether. The nucleophilic component of alkoxyl radical reactivity opens an interesting new access to tetrahydrofuryl amino acids via C,O-cyclization, as shown by synthesis of a N,O-protected 5-phenyltetrahydrofuryl-2-methyl glycine.

• 出版日期2012-12-16