Synthesis of α-Substituted Vinylsulfonium Salts and Their Application as Annulation Reagents in the Formation of Epoxide- and Cyclopropane-Fused Heterocycles
作者:Johnathan V. Matlock、Sven P. Fritz、Stephen A. Harrison、Diane M. Coe、Eoghan M. McGarrigle、Varinder K. Aggarwal
DOI:10.1021/jo501885z
日期:2014.11.7
methods for the synthesis of classes of potentially bioactive molecules remains an important goal for synthetic chemists. Vinylsulfoniumsalts have been used for the synthesis of a wide variety of small heterocyclic motifs; however, further developments to this important class of reagents has been focused on reaction with new substrates rather than development of new vinylsulfoniumsalts. We herein report
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
Asymmetric Ring Opening/Cyclization/Retro-Mannich Reaction of Cyclopropyl Ketones with Aryl 1,2-Diamines for the Synthesis of Benzimidazole Derivatives
reaction of cyclopropyl ketones with aryl 1,2‐diamines has been realized using a chiral N,N′‐dioxide/ScIII catalyst. Benzimidazoles containing chiralsidechains were generated under mild reaction conditions in excellent outcomes (up to 99 % yield and 97 % ee). This method also provides efficient access to chiral benzimidazole‐substituted amide and cycloheptene derivatives.