Kinetics studies of rapid strain-promoted [3+2]-cycloadditions of nitrones with biaryl-aza-cyclooctynone
Kinetics studies of rapid strain-promoted [3+2]-cycloadditions of nitrones with biaryl-aza-cyclooctynone
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DOI：
10.1039/c2ob07165g
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发表时间：
2012-01-01
影响因子：
3.2
通讯作者：
Pezacki, John Paul
中科院分区：
文献类型：
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作者：
McKay, Craig S.;Chigrinova, Mariya;Pezacki, John Paul
应变促进的环硝酮与联芳基-氮杂-环辛炔酮（BARAC）的环加成反应的速率常数高达47.3 M-1 s（-1），这相当于相对于BARAC与苄基叠氮的反应速率提高了47倍，并且比先前报道的应变促进的炔-硝酮环加成反应（SPANC）提高了14倍。使用由Hammett方程定义的线性自由能关系对SPANC反应的研究表明，环加成反应具有0.25 +/- 0.04的rho值，表明反应对取代基不敏感，因此应该具有广泛的适用性。
Strain-promoted cycloadditions of cyclic nitrones with biaryl-aza-cyclooctynone (BARAC) proceed with rate constants up to 47.3 M-1 s(-1), this corresponds to a 47-fold rate enhancement relative to reaction of BARAC with benzyl azide and a 14-fold enhancement over previously reported strain promoted alkyne-nitrone cycloadditions (SPANC). Studies of the SPANC reaction using the linear free energy relationship defined by the Hammett equation demonstrated that the cycloaddition reaction has a rho value of 0.25 +/- 0.04, indicating that reaction is not sensitive to substituents and thus should have broad applicability.