Catalyst-Dependent Chemoselective Formal Insertion of Diazo Compounds into C−C or C−H Bonds of 1,3-Dicarbonyl Compounds
作者:Zhaohong Liu、Paramasivam Sivaguru、Giuseppe Zanoni、Edward A. Anderson、Xihe Bi
DOI:10.1002/anie.201802834
日期:2018.7.16
one‐carbon insertion of diazo compounds into the C−C or C−H bonds of 1,3‐dicarbonyl species is reported. In the presence of silver(I) triflate, diazo insertion into the C(=O)−C bond of the 1,3‐dicarbonyl substrate leads to a 1,4‐dicarbonyl product containing an all‐carbon α‐quaternary center. This reaction constitutes the first example of an insertion of diazo‐derived carbenoids into acyclic C−C bonds. When
An alternative method to Pd-catalyzed Tsuji–Trost reaction is developed and it provides a simpler route for the selective synthesis of a broad range of mono-/bis-allylated and cinnamylated 1,3-dicarbonyl compounds using MMZNiY catalyst at room temperature. Product selectivity can be controlled by the proper choice of catalyst. The catalyst was also well characterized by SEM, TEM, HRTEM, EDAX and X-ray
First example of a heterobimetallic ‘Pd–Sn’ catalyst for direct activation of alcohol: efficient allylation, benzylation and propargylation of arenes, heteroarenes, active methylenes and allyl-Si nucleophiles
作者:Debjit Das、Sanjay Pratihar、Ujjal Kanti Roy、Dipakranjan Mal、Sujit Roy
DOI:10.1039/c2ob25275a
日期:——
Arenes, heteroarenes, 1,3-dicarbonyls and organosilicon nucleophiles undergo highly efficient alkylation with allylic, propargylic and benzylic alcohols in the presence of a new ‘Pd–Sn’ bimetallic catalyst in nitromethane; water being the sole byproduct. The plausible mechanism of alkylation and the intermediacy of ether has been enumerated.
Rhodium/Lewis Acid Catalyzed Regioselective Addition of 1,3-Dicarbonyl Compounds to Internal Alkynes
作者:Wei-Feng Zheng、Qiu-Jing Xu、Qiang Kang
DOI:10.1021/acs.organomet.7b00284
日期:2017.6.26
regioselective addition of 1,3-dicarbonyl compounds to internal alkynescatalyzed by rhodium/Lewisacid catalysts. The corresponding branched/linear allylic alkylation products could be selectively obtained in good yields. Rh–H species were considered to be generated by direct C–H oxidative addition of 1,3-dicarbonyl compounds with rhodium catalyst with the assistance of Lewisacid. Moreover, a retro-allylic
diketones and alkenes under cobalt(II) catalysis and dimethyl sulfoxide involvement. Under optimal conditions, the formation of five- and six-membered rings can be readily controlled by the α-position substitution of styrenes. This process is proposed to proceed through a reaction sequence of oxidative coupling (mediated by K2S2O8), regioselective alkene insertion (promoted by cobalt), and intramolecular
通过在钴 (II) 催化和二甲亚砜参与下偶联二酮和烯烃,实现了一种合成环戊烯和环己烯的独特方法。在最佳条件下,五元环和六元环的形成可以很容易地通过苯乙烯的α位取代来控制。建议该过程通过氧化偶联(由 K 2 S 2 O 8介导)、区域选择性烯烃插入(由钴促进)和所得烯丙基钴物质对羰基或甲基进行分子内攻击的反应序列进行。反应亚甲基工艺。