在伯和仲甲硅烷基醚和芳基醚的存在下,由B(C 6 F 5)3 / Et 3 SiH促进的催化C(sp 3)-O键裂解优先与伯甲苯磺酸盐一起进行。这种反应性的差异使几种1,n-二醇的化学选择性脱官能化,并且正交保护的碳水化合物的羟甲基选择性脱氧突出了新方法的效率。具有邻苯基的甲苯磺酸酯在邻氨基苯甲酸辅助下被裂解。
Cobalt-Catalyzed Ortho Alkylation of Aromatic Imines with Primary and Secondary Alkyl Halides
作者:Ke Gao、Naohiko Yoshikai
DOI:10.1021/ja403759x
日期:2013.6.26
alkylation of aromatic imines with alkyl chlorides and bromides, which allows the introduction of a variety of primary and secondaryalkyl groups at room temperature. The stereochemical outcomes of the reaction of secondaryalkylhalides suggest that the present reaction involves single-electrontransfer from a cobalt species to the alkylhalide to generate the corresponding alkyl radical. A cycloalkylated
Cobalt-Catalyzed Chelation-Assisted Alkylation of Arenes with Primary and Secondary Alkyl Halides
作者:Naohiko Yoshikai、Ke Gao、Takeshi Yamakawa
DOI:10.1055/s-0033-1338658
日期:——
center to the alkylhalide to form the corresponding alkyl radical, which has a finite lifetime before it undergoes C–C bond formation. Cobalt–N-heterocyclic carbene catalytic systems have been developed for chelation-assisted ortho-alkylation of aromatic compounds with alkylhalides. Aryl imines can be selectively monoalkylated at room temperature by various primary or secondary alkyl chlorides or
Here we describe an asymmetric [3,3]-sigmatropicrearrangement of aryl iodanes that enables the enantioselective α-arylation of chiral 2-oxazolines, thereby producing valuable, chiral α-aryl carbonyl compounds. The success of this protocol hinges on the selective assembly of aryl iodanes with 2-oxazolines and the smooth deprotonation of the in situ generated iodonium-imine species. The nearly neutral
Trifluoromethylation of Alkyl Radicals in Aqueous Solution
作者:Haigen Shen、Zhonglin Liu、Pei Zhang、Xinqiang Tan、Zhenzhen Zhang、Chaozhong Li
DOI:10.1021/jacs.7b06044
日期:2017.7.26
The copper-mediated trifluoromethylation of alkyl radicals is described. The combination of Et3SiH and K2S2O8 initiates the radical reactions of alkyl bromides or iodides with BPyCu(CF3)3 (BPy = 2,2'-bipyridine) in aqueous acetone at room temperature to afford the corresponding trifluoromethylation products in good yield. The protocol is applicable to various primary and secondary alkyl halides and
A new method for cross-coupling reaction of alkyl tosylates and bromides with Grignardreagents has been developed by the use of Pd(acac)2 or PdCl2 as the catalyst. Addition of 1,3-butadiene is essential to afford good yields of coupling products. This reaction proceeds efficiently at room temperature using primary and secondary alkyl and aryl Grignardreagents.