Starostzik Marco F, Kenar Jakub, Liu Han-Ying, Mahon Mary F, Hill Michael S
Department of Chemistry, University of Bath, Claverton Down, Bath BA2 7AY, U.K.
Organometallics. 2025 Aug 27;44(17):1987-1997. doi: 10.1021/acs.organomet.5c00272. eCollection 2025 Sep 8.
Reactions of the potassium cyclopropenylaluminates, [{SiN}-Al-η-(CPh)-K] and [{SiN}-Al-η-(PhCCSiMe)-K] with terminal alkynes provide alkynylvinylaluminate derivatives with the silyl-substituted analog providing a level of kinetic discrimination. While this latter behavior results in the regiochemical protonation at Al-C-(Ph) and retention of the more sterically congested Al-C-(SiMe) bond, reactions with CO and phenyl-substituted ketones are complicated by a reduced level of discrimination and a likely tendency toward multiple CO insertion or loss of coordinated alkyne. This latter process results in reactivity more reminiscent of the Al-(I) compounds used to synthesize the cyclopropenylaluminate starting materials. Similar observations are provided by reactions with organic azides and trimethylsilyldiazomethane, which proceed with terminal nitrogen insertion and the generation of azacyclobutenylaluminate structures for [{SiN}-Al-η-(CPh)-K], but with evidence of greater degrees of competitive alkyne elimination from [{SiN}-Al-η-(PhCCSiMe)-K].
环丙烯基铝酸钾[{SiN}-Al-η-(CPh)-K]和[{SiN}-Al-η-(PhCCSiMe)-K]与端炔反应生成炔基乙烯基铝酸盐衍生物，其中硅基取代类似物表现出一定程度的动力学选择性。尽管后一种情况导致在Al-C-(Ph)处发生区域化学质子化，并保留了空间位阻更大的Al-C-(SiMe)键，但与CO和苯基取代酮的反应因选择性降低以及可能存在的多个CO插入或配位炔烃损失的倾向而变得复杂。后一过程导致的反应性更类似于用于合成环丙烯基铝酸盐起始原料的Al-(I)化合物。与有机叠氮化物和三甲基硅基重氮甲烷的反应也有类似的观察结果，[{SiN}-Al-η-(CPh)-K]反应时发生端基氮插入并生成氮杂环丁烯基铝酸盐结构，但[{SiN}-Al-η-(PhCCSiMe)-K]有更多竞争性炔烃消除的迹象。
