Transition metal-catalyzed dehydrogenation is a clean oxidation method requiring no additional oxidants. We have accomplished a heterogeneous Pd/C-catalyzed aqueous dehydrogenation of 1,4-cyclohexadienes and cyclohexenes to give the corresponding highly-functionalized arenes. Furthermore, various arenes could be efficiently constructed in a one-pot manner via a Diels–Alder reaction and the following
Switch in Selectivity for Formal Hydroalkylation of 1,3‐Dienes and Enynes with Simple Hydrazones
作者:Leiyang Lv、Lin Yu、Zihang Qiu、Chao‐Jun Li
DOI:10.1002/anie.201915875
日期:2020.4.16
anti-Markovnikov addition is obtained by changing to a ruthenium catalyst, thus providing direct and efficient access to homoallylic products exclusively. Isotopic substitution experiments indicate that no reversible hydro-metallation across the metal-π-allyl system occurred under ruthenium catalysis. Moreover, this protocol is applicable to the regiospecific hydroalkylation of the distal C=C bond of 1,3-enynes
three-component 1,4-carboamination of dienes is described. Synthetically versatile Weinreb amides were coupled with 1,3-dienes and readily available dioxazolones as the nitrogen source using [Cp*RhCl2 ]2 -catalyzed C-H activation to deliver the 1,4-carboaminated products. This transformation proceeds under mild reaction conditions and affords the products with high levels of regio- and E-selectivity. Mechanistic
Radical-Mediated Heck-Type Alkylation: Stereoconvergent Synthesis of Functionalized Polyenes
作者:Hong Zhang、Xinxin Wu、Yunlong Wei、Chen Zhu
DOI:10.1021/acs.orglett.9b02838
日期:2019.9.20
The stereospecific synthesis of polyenes is of great synthetic value. Disclosed herein is a new, efficient, stereoconvergent approach for the synthesis of functionalized polyenes via a radical-mediated Heck-type alkylation. The easily accessed Z- and E-mixed alkenes are harnessed as starting material, leading to a unique stereoisomer of polyenes. In addition, the transformation features mild reaction
Nickel-Catalyzed Regioselective Hydrobenzylation of 1,3-Dienes with Hydrazones
作者:Leiyang Lv、Dianhu Zhu、Zihang Qiu、Jianbin Li、Chao-Jun Li
DOI:10.1021/acscatal.9b02483
日期:2019.10.4
Hydroalkylation of unsaturated hydrocarbons with unstabilized carbonnucleophiles is difficult and remains a major challenge. The disclosed examples so far have mainly focused on the involvement of heteroatom and/or stabilized carbonnucleophiles as efficient reaction partners. Reported here is an unprecedented regioselective nickel-catalyzed hydrobenzylation of 1,3-dienes with hydrazones, generated in situ from