Cyclization of unsaturated monoterpenic alcohols mediated by thallium (III) salts
作者:Helena M.C. Ferraz、Carlos M.R. Ribeiro、Mônica V.A. Grazini、Timothy J. Brocksom、Ursula Brocksom
DOI:10.1016/s0040-4039(00)76741-4
日期:1994.3
thallium trinitrate with four monoterpenic unsaturated alcohols (isopulegol, neo-isopulegol, cis-carveol and α-terpineol), in AcOH:H2O (1:1, vol/vol) as solvent, led to the corresponding β-hydroxy-cyclic ethers with high regio- and stereoselectivity, in moderate to good yields. A mechanism of ring-contraction or ring-expansion of the oxythallated adduct is proposed, based on the substitution patterns of
三乙酸th和三硝酸th与四种单萜类不饱和醇(异萜烯醇,新异异薄荷醇,顺式香芹酚和α-松油醇)在AcOH:H 2 O(1:1,vol / vol)中的反应导致相应的具有高区域和立体选择性的β-羟基环醚,产率中等至良好。基于每个双键的取代方式,提出了一种缩醛化的加合物的缩环或扩环机理。