4265-25-2Relevant articles and documents
Highly Efficient Synthesis of 2-Substituted Benzo[ b ]furan Derivatives from the Cross-Coupling Reactions of 2-Halobenzo[ b ]furans with Organoalane Reagents
Wen, Chang,Wu, Chuan,Luo, Ruiqiang,Li, Qinghan,Chen, Feng
supporting information, p. 3847 - 3861 (2021/07/02)
A highly efficient and simple route for the synthesis of 2-substituted benzo[ b ]furans has been developed by palladium-catalyzed cross-coupling reaction of 2-halobenzo[ b ]furans with aryl, alkynyl, and alkylaluminum reagents. Various 2-aryl-, 2-alkynyl-, and 2-alkyl-substituted benzo[ b ]furan derivatives can be obtained in 23-97% isolated yields using 2-3 mol% PdCl 2/4-6 mol% XantPhos as the catalyst under mild reaction conditions. The aryls bearing electron-donating or electron-withdrawing groups in 2-halobenzo[ b ]furans gave products in 40-97% isolated yields. In addition, aluminum reagents containing thienyl, furanyl, trimethylsilanyl, and benzyl groups worked efficiently with 2-halobenzo[ b ]furans as well, and three bioactive molecules with 2-substituted benzo[ b ]furan skeleton were synthesized. Furthermore, the broad substrates scope and the typical maintenance of vigorous efficiency on gram scale make this protocol a potentially practical method to synthesize 2-substituted benzo[ b ]furan derivatives. On the basis of the experimental results, a possible catalytic cycle has been proposed.
Synthesis of Chiral Polycyclic Tetrahydrocarbazoles by Enantioselective Aminocatalytic Double Activation of 2-Hydroxycinnamaldehydes with Dienals
Ming, Yong-Chao,Lv, Xue-Jiao,Liu, Ming,Liu, Yan-Kai
supporting information, p. 6515 - 6519 (2021/09/02)
An efficient aminocatalytic enantioselective double-activation strategy has been developed that combines several different aminocatalytic modes in a cascade process, such as iminium ion, vinylogous iminium ion, trienamine, and dienamine activations. By using this strategy, 2-hydroxycinnamaldehydes worked well with various dienals via [4 + 2] cycloaddition and the oxa-Michael reaction-initiated cascade, respectively, leading to chiral polycyclic tetrahydrocarbazole and chromane derivatives with excellent diastereo- and enantioselectivities.
Discovery of orthogonal synthesis using artificial intelligence: Pd(OAc)2-catalyzed one-pot synthesis of benzofuran and bicyclo[3.3.1]nonane scaffolds
Takabatake, Tetsuhiko,Fujiwara, Keisuke,Okamoto, Sho,Kishimoto, Ryo,Kagawa, Natsuko,Toyota, Masahiro
, (2020/08/10)
A synthetic route for the common intermediate, methyl 2-formylbenzofuran-7-carboxylate (7a), to efficiently assemble three bioactive benzofurans 4–6 was explored using the artificial intelligence system SYNSUP. Among the routes proposed by SYNSUP, we investigated a three-step synthesis of 7a using methyl 4-ally-3-oxohept-6-enoate (10). A new catalytic reaction was found in which 7a was directly obtained from 10 in a single step with a yield of 24percent. It was found that this chemical yield could be increased to 74percent when methyl 3-allyl-2-hydroxybenzoate (9a), an intermediate of the above one-pot transformation, was subjected to the catalytic process. In addition, in this catalytic process, 8a (76percent) and 11 (77percent) were each selectively synthesized from 10 by changing only the solvent. Therefore, we created a novel orthogonal synthesis of methyl 2-methylbenzofuran-7-carboxylate (8a) and methyl 9-oxobicyclo[3.3.1]nona-3,6-diene-1-carboxylate (11). Finally, the total syntheses of bioactive benzofurans 4–6 were completed smoothly using 7a and 8a.
