[3,3]-Sigmatropic Rearrangement/5-<i>exo</i>-<i>dig</i> Cyclization Reactions of Benzyl Alkynyl Ethers: Synthesis of Substituted 2-Indanones and Indenes
作者:Armen A. Tudjarian、Thomas G. Minehan
DOI:10.1021/jo200271s
日期:2011.5.6
Substituted benzyl alkynyl ethers, prepared from the corresponding α-alkoxy ketones in a two-step sequence involving enol triflate formation and KOtBu-induced E2 elimination, undergo [3,3]-sigmatropic rearrangement/intramolecular 5-exo-dig cyclization at 60 °C to form substituted 2-indanones in good overall yields. 1,3-cis-Disubstituted-2-indanones are formed preferentially when the benzylic substituent
取代的苄基的炔醚,从在两步骤序列相应的α -烷氧基酮涉及烯醇三氟甲磺酸形成和KO制备吨卜诱导E2消除,经历[3,3] -sigmatropic重排/分子内-5-外-挖环化在60 °C 以良好的总产率形成取代的 2-茚满酮。当苄基取代基R 1较大时,1,3-顺式-二取代-2-茚满酮优先形成。取代的茚可以通过霍纳-沃兹沃思-埃蒙斯反应以高产率从 2-茚满酮制备。
Synthesis of Ketones by C−H Functionalization of Aldehydes with Boronic Acids under Transition‐Metal‐Free Conditions
作者:Silvia Roscales、Aurelio G. Csáky
DOI:10.1002/anie.202015835
日期:2021.4.12
A method for the synthesis of ketones from aldehydes and boronic acids via a transition‐metal‐free C−H functionalization reaction is reported. The method employs nitrosobenzene as a reagent to drive the simultaneous activation of the boronic acid as a boronate and the activation of the C−Hbond of the aldehyde as an iminium species that triggers the key C−C bond‐forming step via an intramolecular migration