Oxidative radical cyclisations for the synthesis of γ-lactones
作者:Luke H. Powell、Paul H. Docherty、David G. Hulcoop、Paul D. Kemmitt、Jonathan W. Burton
DOI:10.1039/b802473a
日期:——
The use of manganese(III) acetate in combination with copper(II) triflate allows the synthesis of [3.3.0]-bicyclic gamma-lactones from 4-pentenylmalonates in excellent yields.
The iodocarbocyclizationreactions of 4-pentenylmalonate derivatives using 20 mol% of the chiral titanium complex in the presence of 12 end 2,6-dimethoxypyridine proceeded with high enantioselectivity to give good yields of cyclopentane derivatives. The origin of enantioselectivity in the present reaction is discussed on the basis of X-ray crystal structural data of the chiral titanium complex from
In the presence of SnCl4 and Et3N, intramolecular carbostannation reaction of various active methine compounds having an unactivated alkenyl, alkynyl, or allenyl group proceeds in good yields with complete regioselectivity. The subsequent reaction of the resulting Sn intermediates with-some electrophiles provides functionalized cyclopentane and cyclohexane derivatives.
Atom transfer cyclization reactions of .alpha.-iodo esters, ketones, and malonates: examples of selective 5-exo, 6-endo, 6-exo, and 7-endo ring closures