Mechanochemical Assisted Chemoselective and Stereoselective Hydrogen‐Bonding Catalyzed Addition of Dithiomalonates to Enones
作者:Żaneta A. Mała、Mikołaj J. Janicki、Robert W. Góra、Krzysztof A. Konieczny、Rafał Kowalczyk
DOI:10.1002/adsc.202300636
日期:2023.10.13
be active nucleophiles in the stereoselectiveadditions to chalcones, dienones, and en-ynones affording the desired Michael adducts with moderate to good yield and enantioselectivities up to 98%. In contrast, the analogous dibenzyl malonate remained inactive. Bifunctional Cinchona squaramides secured the effective chirality transfer and the selectivity towards Michael adducts of various bisthiomalonates
A tandem [3 + 2] cycloaddition/reductive cyclization of nitrochalcones with activated methylene isocyanides for the efficient synthesis of pyrrolo[2,3-b]quinolones is reported. In this reaction, the in situ generated dihydropyrroline acts as the internal reductant to convert the nitro into an electrophilic nitroso group, which undergoes subsequent C–N bond formation. Transition-metal-free, simple experimental
报道了用活化的亚甲基异氰酸酯串联硝唑烷的[3 + 2]环加成/还原环化反应,可有效合成吡咯并[2,3- b ]喹诺酮。在该反应中,原位生成的二氢吡咯啉充当内部还原剂,将硝基转化为亲电的亚硝基,随后发生C–N键的形成。不含过渡金属,简单的实验程序以及易于使用的起始材料构成了目前的转化方式。
Transition Metal-Free Iodine-Catalyzed Denitrative C–S Cross-Coupling: An Atypical Route to Access Thiochromane Derivatives
作者:Anuradha Nandy、Govindasamy Sekar
DOI:10.1021/acs.joc.2c00425
日期:2022.6.3
extended for a three-component synthesis of thiochromenes via intermolecular C–S cross-coupling followed by aldol reaction. The reaction proceeds via activation of the keto group of chalcone through a halogenbond complex with iodine/denitrative C–S bond formation with xanthate/sulfa-Michael addition to chalcones. The methodology was also demonstrated for chemoselective reduction of chalcones. The protocol