Gas chromatography/electron impact mass spectrometry applied to the differentiation of the positional isomers of long-chainn-alkylcyclohexanones
摘要:
AbstractThe influence of n‐butyl group position upon the fragmentation behavior of the three isomeric n‐butylcyclohexanones was studied. The different fragmentation processes are described and have been applied to the differentiation of the positional isomers of long‐chain n‐alkylcyclohexanones. In the case of the 4‐n‐alkyl isomers, an interesting mechanism involving a recyclization is proposed and substantiated by deuterium labelling.
SmI2-Mediated coupling reactions between iodoalkynes and ketones or aldehydes to give propargyl alcohols
作者:Munetaka Kunishima、Shinobu Tanaka、Kazuhiro Kono、Kazuhito Hioki、Shohei Tani
DOI:10.1016/0040-4039(95)00659-z
日期:1995.5
Samarium iodide (SmI2) mediates a coupling reaction between alkynyl iodides and ketones or aldehydes to give propargyl alcohols in the presence of hexamethylphosphoric triamide (HMPA) in either benzene or tetrahydrofuran (THF). An alkynylsamarium is involved as an intermediate.
Synthesis of some novel steroidal 1,2,4,5-tetraoxanes
作者:Archana M. Das、Manash P. Hazarika
DOI:10.1039/c5ra00169b
日期:——
A facile synthesis of A-ring manipulated C-20 methyl carboxylate steroid derivative with unsymmetrical dispiro 1,2,4,5-tetraoxanes has been focused herein via acid catalyzed cyclocondensation of bis-epidioxy ketone. Novel stable unsymmetrical steroidal based spirocycloalkane 1,2,4,5 tetraoxane 8 has been developed from 3β-acetoxy-pregn-5(6), 16(17)-diene-20-one (16-dehydropregnenolone acetate, i.e
Direct synthesis of ring-fused quinolines and pyridines catalyzed by <i>NN</i><sub><i>H</i></sub><i>Y</i>-ligated manganese complexes (Y = NR<sub>2</sub> or SR)
作者:Zheng Wang、Qing Lin、Ning Ma、Song Liu、Mingyang Han、Xiuli Yan、Qingbin Liu、Gregory A. Solan、Wen-Hua Sun
DOI:10.1039/d1cy01945g
日期:——
Four cationic manganese(I) complexes, [(fac-NNHN)Mn(CO)3]Br (Mn-1–Mn-3) and [(fac-NNHS)Mn(CO)3]Br (Mn-4) (where NNH is a 5,6,7,8-tetrahydro-8-quinolinamine moiety), have been synthesized and evaluated as catalysts for the direct synthesis of quinolines and pyridines by the reaction of a γ-amino alcohol with a ketone or secondary alcohol; NNHS-ligated Mn-4 proved the most effective of the four catalysts
四种阳离子锰( I )配合物,[( fac-NN H N )Mn(CO) 3 ]Br ( Mn-1 – Mn-3 ) 和 [( fac-NN H S )Mn(CO) 3 ]Br ( Mn -4 )(其中N H是 5,6,7,8-四氢-8-喹啉胺部分),已被合成并评估为通过 γ-氨基醇与酮或仲醇;NN H S -连接的Mn-4被证明是四种催化剂中最有效的。在催化剂负载量为 0.5-5.0 mol% 的情况下,反应进行得很好,并且可以耐受不同的官能团,如烷基、环烷基、烷氧基、氯化物和杂芳基。基于 DFT 计算和实验证据,提出了一种涉及无受体脱氢偶联 (ADC) 的机制。值得注意的是,这种基于锰的催化方案为广泛合成重要的取代单环、双环和三环N-杂环(包括 50 个喹啉和 26 个吡啶实例)提供了一条有前途的绿色环保途径,分离产率高达 93 %。
A stable 1:1 lithium acylcyanocuprate. Dependence of the stability of acylcyanocuprates on the nature of the alkyl substituent.
作者:Dietmar Seyferth、Richard C. Hui
DOI:10.1016/s0040-4039(00)84288-4
日期:1986.1
Acylcuprates obtained by carbonylation of R(CN)CuLi cuprates (R = t-Bu, sec-Bu) at low temperature are effective in the directnucleophilic1,4-acylation of α,β-unsaturated ketones and aldehydes. The R = t-Bu reagent is sufficiently stable so that it can be used even at room temparature. The R = sec-Bu reagent is best used at −110°C.
Nickel-Catalyzed Reductive Cross-Coupling of Unactivated Alkyl Halides
作者:Xiaolong Yu、Tao Yang、Shulin Wang、Hailiang Xu、Hegui Gong
DOI:10.1021/ol200617f
日期:2011.4.15
Ni-catalyzed reductive approach to the cross-coupling of two unactivated alkyl halides has been successfully developed. The reaction works efficiently for primary and secondary halides, with at least one being bromide. The mildreaction conditions allow for excellent functional group tolerance and provide the C(sp3)−C(sp3) coupling products in moderate to excellent yields.