Controlled Payne rearrangements of 2,3-epoxy alcohols in aprotic media: an enantioselective total synthesis of (+)-exo-brevicomin
作者:Philip C. Bulman Page、Christopher M. Rayner、Ian O. Sutherland
DOI:10.1039/c39880000356
日期:——
The catalysis of the isomerisation of primary cis-2,3-epoxy alcohols to threo-1,2-epoxy alcohols by lithium chloride in tetrahydrofuran solution is described; the more reactive terminal epoxides may be selectively trapped in situ by reaction with nucleophiles, and this methodology is used in an enantioselectivesynthesis of (+)-exo-brevicomin.
Amidocuprates, derived from organocopperreagents and lithium amides upon exposure to oxygen at low temperature, provide new amine derivatives in satisfactory yields. Details of this flexible and simple methodology are given. The reaction mechanism is analyzed in terms of an oxidative intramolecular coupling of aminyl radicals with the ligands on Cu in the intermediate amidocuprate. This reaction is
Reactions of some -ribonolactone derivatives with alkyl cuprates synthesis of (+)-eldanolide and (+)--cognac lactone
作者:Rosa M. Ortuño、Ramon Merce、Josep Font
DOI:10.1016/s0040-4020(01)90327-8
日期:1987.1
Reactions of some -ribonolactone derivatives with alkyl cuprates have been investigated in order to obtain molecules with a (4,5)-4,5-dialkyldihydro-2(3)-furanone type constitution. As a direct application, (+)-eldanolide and (+)--cognac lactone have been synthetized.
An efficientsynthesis of chiral quaternary carbon centres via Me2Cu(CN)Li2·BF3 or RCu(CN)Li·BF3(R ≠ Me) mediated 1,3-chirality transfer of α-alkyl-γ-mesyloxy-α,β-enoates is reported.