Department of Chemistry, Ben-Gurion University of the Negev , Beer-Sheva 841051, Israel.
Justus-Liebig University , Heinrich-Buff-Ring 17, 35392 Giessen, Germany.
J Am Chem Soc. 2017 Jul 12;139(27):9097-9099. doi: 10.1021/jacs.7b04593. Epub 2017 Jun 29.
Using the tunneling-controlled reactivity of cyclopropylmethylcarbene, we demonstrate the viability of isotope-controlled selectivity (ICS), a novel control element of chemical reactivity where a molecular system with two conceivable products of tunneling exclusively produces one or the other, depending only on isotopic composition. Our multidimensional small-curvature tunneling (SCT) computations indicate that, under cryogenic conditions, 1-methoxycyclopropylmethylcarbene shows rapid H-migration to 1-methoxy-1-vinylcyclopropane, whereas deuterium-substituted 1-methoxycyclopropyl-d-methylcarbene undergoes ring expansion to 1-d-methylcyclobutene. This predicted change in reactivity constitutes the first example of a kinetic isotope effect that discriminates between the formation of two products.
利用环丙甲基卡宾的隧道控制反应性，我们证明了同位素控制选择性（ICS）的可行性，ICS 是化学反应性的一种新型控制元件，其中具有两种可想象的隧道产物的分子系统仅根据同位素组成排他性地产生一种或另一种产物。我们的多维小曲率隧道（SCT）计算表明，在低温条件下，1-甲氧基环丙甲基卡宾迅速发生 H 迁移生成 1-甲氧基-1-乙烯基环丙烷，而氘取代的 1-甲氧基环丙基-d-甲基卡宾则发生环扩张生成 1-d-甲基环丁烯。这种预测的反应性变化构成了首例区分两种产物形成的动力学同位素效应的例子。
