Rhenium-Catalyzed Phthalide Synthesis from Benzamides and Aldehydes via C–H Bond Activation
作者:Bing Jia、Yunhui Yang、Xiqing Jin、Guoliang Mao、Congyang Wang
DOI:10.1021/acs.orglett.9b02142
日期:2019.8.16
The [4 + 1] annulation of benzamides and aldehydes for phthalide synthesis was achieved via rhenium-catalyzed C–H activation, which demonstrates an unprecedented reaction pattern distinct from those of other transition-metal catalyses. The reaction also features readily available starting materials, a wide scope for both electro-rich and electro-deficient substrates, and the elimination of homoannulation
Addition of arylzincs to aldehydes was achieved by making use of the novel transmetallation of arylzincs into Cr3+ compounds. Various α-substituted benzyl alcohols or 3-substituted 1(3H)-isobenzofuranones, containing reactive functional groups, were synthesized in good yields. Me3SiCl exerted beneficial effects on the reaction.
Nucleophilic Additions of Arylzinc Compounds to Aldehydes Mediated by CrCl<sub>3</sub>: Efficient and Facile Synthesis of Functionalized Benzhydrols, 1(3<i>H</i>)-Isobenzofuranones, Benzyl Alcohols, or Diaryl Ketones
benzhydrols 4a-f in good yields. From arylzinc compounds 1a,b, 3-aryl-1(3H)-isobenzofuranones 3a-f were given by the CrCl(3)-mediated reaction with arylaldehydes 2a-f. Diaryl ketones 5a-e were obtained in good yields by the addition of excess amount of benzaldehyde as an oxidant to the resulting solution after the CrCl(3)-mediated reaction between arylzinc compounds 1c-g and arylaldehydes 2b,g was completed
Halogen–magnesium exchange on unprotected aromatic and heteroaromatic carboxylic acids
作者:Felix Kopp、Stefan Wunderlich、Paul Knochel
DOI:10.1039/b618923g
日期:——
The magnesiation of halogenated aromatic and heteroaromatic carboxylic acids is accomplished by their treatment with MeMgCl in the presence of LiCl and subsequent reaction with i-PrMgCl·LiCl; the resulting double-magnesiated species react with a variety of electrophiles in up to 97% yield.
zed carbonylations involved either toxic carbon monoxide (CO) gas as carbonylating agent or functional-group-assisted ortho sp2 C–H activation (i.e., ortho acylation) or carbonylation by activation of the carbonyl group (i.e., via the formation of enamines). Contradicting these methods, here we describe an environmentally benign process, [Pd]-catalyzed direct carbonylation starting from simple and