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
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
The asymmetricring‐openingreaction of cyclopropyl ketones with indoles has been realized by using a N,N′‐dioxide/scandium(ΙΙΙ) complex as catalyst. The corresponding 3‐alkylated indole derivatives were obtained in moderate to excellent yields with good ee values. Moreover, a possible transition state was proposed on the basis of experimental studies and X‐ray structure of product.
investigated by using the aziridine ring capability to act as a directing metalation group. Trapped with electrophiles, the resulting o-aziridinyl benzyllithium 1-Li gives access to several functionalized aziridines 2a−j. The hydroxyalkylated derivatives 2d−j were converted into important scaffolds such as isochromans 3a−d. A stereoselective preparation of isochromans (R)-3b, (1R,3S)-3d, and (1R,3R)-3d has been
base-promoted [2+1] annulationreaction has been developed for the synthesis of the structural diversity C2-spirocyclopropyl-indolin-3-ones. This [2+1] annulation process using simple and easily prepared nucleophilic indolin-3-ones (as C1 synthons) and bromosulfonium salts (as C2 synthons) as substrates, and realized the synthesis of C2-spirocyclopropyl-indolin-3-ones with up to 99 % yield and >20 : 1 dr.
已经开发了一种简单有效的碱促进 [2+1] 环化反应,用于合成结构多样性 C2-spirocyclopropyl-indolin-3-ones。这种[2+1]环化过程以简单易制备的亲核三氢吲哚-3-酮(C1合成子)和溴硫盐(C2合成子)为底物,实现了C2-螺环丙基-3-二氢吲哚-酮的合成高达 99% 的产率和 >20 : 1 dr.