A sequential [4 + 2]/[2 + 1] annulation of α-aryl vinylsulfoniums with 2-aminochalcones and 2-(2-aminobenzylidene)-1H-indene-1,3(2H)-dione is reported that affords a series of cyclopropane-fused tetrahydroquinolines. The salient features of this novel and practical transformation include high efficiency, transition-metal-free nature, operational simplicity, and outstanding functional group tolerance
Iodine‐catalyzed ring opening of 1,1‐diacylcyclopropanes for synthesis of fully substituted pyrazole derivatives have been reported. This reaction tolerates a broad range of cyclopropyl ketones and sulfonyl hydrazides to afford useful and densely functionalized pyrazole derivatives with a hydroxy functional group.
Asymmetric Ring-Opening of Cyclopropyl Ketones with Thiol, Alcohol, and Carboxylic Acid Nucleophiles Catalyzed by a Chiral<i>N</i>,<i>N</i>′-Dioxide-Scandium(III) Complex
efficient asymmetricring‐openingreaction of cyclopropyl ketones with a broad range of thiols, alcohols and carboxylic acids has been first realized by using a chiral N,N′‐dioxide–scandium(III) complex as catalyst. The corresponding sulfides, ethers, and esters were obtained in up to 99 % yield and 95 % ee. This is also the first example of one catalytic system working for the ring‐openingreaction of donor–acceptor
The asymmetricring‐opening/cyclization of cyclopropyl ketones with primary amine nucleophiles was catalyzed by a chiral N,N′‐dioxide/scandium(III) complex through a kinetic resolution process. A broad range of cyclopropyl ketones and primary amines are suitable substrates of this reaction. The corresponding products were afforded in excellent enantioselectivities and yields (up to 97 % ee and 98 %
A highly diastereo- and enantioselective [3 + 3] annulation of donor–acceptor cyclopropanes with mercaptoacetaldehyde has been developed. In the presence of a N,N′-dioxide–Sc(III) complex as the catalyst, a number of aromatic substituted cyclopropylketones reacted with mercaptoacetaldehyde smoothly, providing the corresponding chiral tetrahydrothiopyranols in moderate yields with excellent ee (up