开发了在亚磷酸二乙酯存在下吡啶鎓盐和三甲基硅烷基氰化物 (TMSCN) 的铜催化反应。该反应首次实现了从容易获得的起始材料一步构建生物学上重要的2-氰基咪唑并[1,2- a ]吡啶的反应,并且在克级是可行的。该协议的范围通过 27 个示例进行了演示。在这一一锅法中可以实现连续的双氰化和环化。TMSCN 发挥双重作用,不仅作为“CN”源,而且作为咪唑并[1,2- a ]吡啶环化的偶联伙伴。
作者:Hon Man Yau、Si Jia Chan、Stephen George、James Hook、Anna Croft、Jason Harper
DOI:10.3390/molecules14072521
日期:——
recent years to characterise ionicliquids in terms of parameters that are well described for molecular solvents, using these to explain reaction outcomes remains problematic. Herein we propose that many reaction outcomes in ionicliquids may be explained by considering the electrostatic interactions present in the solution; that is, by recognising that ionicliquids are salts. This is supported by evidence
The internalenergy distribution P(Eint) of ions emitted in an electrospray (ESI) source interfaced with a sector massspectrometer is evaluated by using the experimental survival yield (SY) method including the kinetic shift. This method is based on the relationship between the degree of fragmentation of an ion and its amount of internalenergy and uses benzylpyridinium cations due to their simple
‘One-pot’ Hammett plots: a general method for the rapid acquisition of relative rate data
作者:Hon Man Yau、Anna K. Croft、Jason B. Harper
DOI:10.1039/c2cc34074g
日期:——
A general âone-potâ method for determining relative rates of reaction in complex mixtures has been established using free energy relationships to demonstrate its utility. Competition experiments involving as many as seven species gave relative rate constants that are in good agreement to those obtained from individual kinetic analyses.
Solvent reorganisation as the driving force for rate changes of Menschutkin reactions in an ionic liquid
作者:Hon Man Yau、Andrew G. Howe、James M. Hook、Anna K. Croft、Jason B. Harper
DOI:10.1039/b909171h
日期:——
The effect on the rate of reaction of each of a series of Menschutkin processes on changing from a molecular solvent to an ionic liquid was investigated. In each case, the rate acceleration observed at room temperature could be attributed to the change in the entropy of the system on reaching the transition state, offsetting any enthalpic cost.
<sup>79</sup>Br NMR spectroscopy as a practical tool for kinetic analysis
作者:Si Jia Chan、Andrew G. Howe、James M. Hook、Jason B. Harper
DOI:10.1002/mrc.2401
日期:2009.4
(79)Br NMRspectroscopy has been used to monitor a series of reactions in which the bromide ion is produced, including the Menschutkin reaction of pyridine with a range of substituted benzyl bromides and a Heck coupling process. In cases where the process could also be monitored using (1)H NMRspectroscopy, the kinetic analyses using heteronuclear magnetic resonance spectroscopy were shown to be completely