amount of InCl3 and aceticanhydride remarkably promotes the Knoevenagel condensation of a variety of aldehydes and activated methylene compounds. This catalytic system accommodates aromatic aldehydes containing a variety of electron-donating and -withdrawing groups, heteroaromatic aldehydes, conjugate aldehydes, and aliphatic aldehydes. Central to successfully driving the condensation series is the formation
Catalytic asymmetric synthesis of hydrothiazole derivatives was developed via a well-organized formal [2 + 1 + 2] cycloaddition reaction triggered by asymmetric addition of isocyanide to alkylidene malonate. Various chiral hydrothiazole derivatives were readily provided in good yield with high enantioselectivity (up to 98% yield, 98.5:1.5 er) utilizing a chiral Mg(OTf)2/N,N'-dioxide complex as the
the addition to various unsaturated carbonyl compounds, while calcium triflimide [Ca(NTf2)2] efficiently catalyzed the addition to nitroolefins. Friedel–Crafts alkylation of indole and its derivatives with a variety of electron-deficient alkenes catalyzed by Mg and Ca salts has been studied. The dependence of the results on the nature of the starting olefins, substituents on indole, and Michael acceptors
Lewis Acid‐Catalyzed Formal (4+2)‐ and (2+2+2)‐Cycloaddition Between 1‐Azadienes and Styrylmalonates as Analogues of Donor‐Acceptor Cyclopropanes
作者:Pavel G. Sergeev、Roman A. Novikov、Yury V. Tomilov
DOI:10.1002/adsc.202100453
日期:2021.12.7
known (3+2)-cycloaddition synthetic methodology. Based on the results obtained, a method for the diastereoselective synthesis of substituted trans,trans-tetrahydropyridines was developed. Three substrate-sensitive diverse Lewis acid catalytic systems have been employed based on Sc(OTf)3, Sn(OTf)2, and GaCl3. The use of GaCl3 as a Lewis acid allows to obtain a minor product of the formal (2+2+2)-cycloaddition