Organosilicon compounds are important reagents and synthetic intermediates that play a key role in the construction of new materials and complex products. Here we show a highly diastereoselective rhodium-catalyzed cycloisomerization of 1,6-dienes, in which the use of (EtO)3SiH accelerates the intramolecular cyclization reaction to afford a novel spiro-fused succinimide and pyrazolone derivatives in moderate
有机硅化合物是重要的试剂和合成中间体,在新材料和复杂产品的构建中起着关键作用。在这里,我们展示了一种高度非对映选择性的铑催化的 1,6-二烯环化异构化,其中使用 (EtO) 3 SiH 加速了分子内环化反应,以中等至优异的产率提供了新型螺稠合琥珀酰亚胺和吡唑啉酮衍生物。单一的非对映异构体。所提出的机制涉及来自氢硅烷的活性 Rh-H 物质,该物质是该螺型环异构化反应中的 H 供体。
Spirocyclizations Involving Oxonium Ylides Derived from Cyclic α-Diazocarbonyl Compounds: An Entry into 6-Oxa-2-azaspiro[4.5]decane Scaffold
insertion into a tetrahydrofuran molecule. This competing process gave compoundsbased on the 3-(tetrahydrofur-2-yl)pyrrolidine scaffold, which are also relevant from the medicinal chemistry standpoint. These findings enrich the available arsenal of metal-catalyzed spirocyclization methods based on the use of cyclic diazocompounds.
Convenient preparation of (E)-3-arylidene-4-diazopyrrolidine-2,5-diones in array format
作者:Evgeny G. Chupakhin、Grigory P. Kantin、Dmitry V. Dar’in、Mikhail Krasavin
DOI:10.1016/j.mencom.2021.01.010
日期:2021.1
Iterative Arylation of Itaconimides with Diazonium Salts through Electrophilic Palladium Catalysis: Divergent β-H-Elimination Pathways in Repetitive Matsuda–Heck Reactions
base-free conditions. Notable features are high isolated yields, regio- and stereoselectivities, and short reaction times. In a comparative investigation, aryl iodides, bromides, and triflates were shown to be inferior coupling reagents in this reaction. The 3-arylmethylidene pyrrolidine-2,5-diones undergo second Matsuda–Heck coupling, which proceeds via endo-selective β-H-elimination to give diarylmethyl-substituted