Phosphine-catalyzed [4+1] annulation of 1,3-(aza)dienes with maleimides: highly efficient construction of azaspiro[4.4]nonenes
作者:Mei Yang、Tianyi Wang、Shixuan Cao、Zhengjie He
DOI:10.1039/c4cc05624h
日期:——
Phosphine-catalyzed [4+1] annulation of electron-deficient 1,3-dienes or 1,3-azadienes with maleimides has been successfully developed under very mild conditions, providing a convenient and highly efficient method for constructing 2-azaspiro[4.4]nonenes and 1,7-diazaspiro[4.4]nonenes. This reaction represents the first example of [4+1] cyclization between electron-deficient 4pi-conjugated systems and
Diastereodivergent synthesis of cyclopropanes <i>via</i> on-water [2 + 1] annulations of diazo compounds with electron-deficient alkenes
作者:Qing-Zhu Li、Xiang Zhang、Ke Xie、Qing-Song Dai、Rong Zeng、Yan-Qing Liu、Zhi-Qiang Jia、Xin Feng、Jun-Long Li
DOI:10.1039/c9gc00278b
日期:——
cyclopropanation of diazo compounds and electron-deficient alkenes under metal- and catalyst-freeconditions was developed. The use of water as the sole solvent dramatically increased the efficiency of the reaction. This on-water synthesis approach featured numerous advantages, including high yield, broad substrate scope and environmentally friendly conditions. Moreover, a simple substrate-engineering strategy was
A PPh3 mediated reductive annulation reactionbetweenisatins and 4,4-dicyano-2-methylenebut-3-enoates was developed. The reaction provided an alternative method for constructing five- and three-membered all-carbon spirooxindole compounds. Lithium chloride as a Lewis acid played a key role in the synthesis of spirocyclopentenyl oxindole compounds.
A kinetically controllable strategy toward the construction of otherwise challenging nine-memberedcarbocycles is reported. This Pd-catalyzed decarboxylative procedure utilizes vinyl methylene cyclic carbonates as the C5-dipole and allylidenemalononitriles as C4-building blocks. The protocol features user-friendly operations with controllable regioselectivity and generates CO2 as the sole byproduct
报道了一种用于构建具有挑战性的九元碳环的动力学可控策略。这种 Pd 催化的脱羧过程使用乙烯基亚甲基环状碳酸酯作为 C5-偶极子和烯丙基丙二腈作为 C4 结构单元。该协议的特点是用户友好的操作和可控的区域选择性,并产生 CO 2作为唯一的副产物。还研究了合成有价值和热力学有利的七元碳环的形成。