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.
应变促进环腈纶与双芳基
叠氮环辛酮(B
ARAC)的环加成反应的速率常数高达 47.3 M-1 s-1,与 B
ARAC 与
叠氮化苄反应相比,速率提高了 47 倍,与之前报道的应变促进
炔烃-硝酮环加成反应(S
PANC)相比,速率提高了 14 倍。利用哈米特方程定义的线性自由能关系对 S
PANC 反应进行的研究表明,该环化反应的 rho 值为 0.25 ± 0.04,表明该反应对取代基不敏感,因此具有广泛的适用性。