“Deficient” but “efficient”, the first example of a catalytic Friedel–Craftsalkylation of arenes, carrying electron-withdrawing groups, with alcohols is reported. The optimized iron(III) chloride (97%) catalyzed allylation, benzylation and propargylation procedures open an access to a range of tetrahydronaphthalenes, tetrahydroisoquinolines and tetrahydrobenzo[d]azepines featuring tertiary benzylic
据报道,“有缺陷”但“有效率”是带有醇类的带有吸电子基团的芳烃催化弗里德-克拉夫茨烷基化的第一个例子。经过优化的氯化铁(III)(97%)催化的烯丙基化,苄基化和炔丙基化程序使人们可以使用一系列具有叔苄基立体中心的四氢萘,四氢异喹啉和四氢苯并[ d ]氮杂s烷,产率高(高达92%),反应时间短。时代。
1,5 vs. 1,6 Intramolecular homolytic aromatic substitution by vinyl radicals
Manganese(III) acetate oxidation of substituted diethyl benzylmalonates in the presence of alkynes affords tetrahydronaphthalene derivatives 3, 6, 7 and spiro[4,5]decatriene derivatives 4 or 5, through competitive 1,5 and 1,6 intramolecular aromatic substitution by vinyl radicals.
Synthesis of substituted tetrahydronaphthalenes by manganese(III), cerium(IV), and iron(III) oxidation of substituted diethyl .alpha.-benzylmalonates in the presence of olefins
The oxidation of substituted diethyl alpha-benzylmalonates (1a-m) by manganese(III) acetate in acetic acid, cerium(IV) ammonium nitrate in methanol, or iron(III) perchlorate in acetonitrile in the presence of substituted olefins 2a-u was investigated. The results are consistent with a common mechanism. It involves selective generation of malonyl radicals from high-valent metal malonyl complexes, their addition to the olefin, and competition of the adduct radical between intramolecular cyclization to produce highly functionalized tetrahydronaphthalenes (3) and oxidation by metal salt to give mainly gamma-lactones (5). Several electron-withdrawing and releasing substituents on the aromatic ring and on the olefin can be successfully used in the synthesis of 3 without olefin telomerization. The influence of metal and olefin or aromatic substituents on the homolytic addition and intramolecular aromatic substitution is discussed.