Phosphaaluminirenes: Synthons for Main Group Heterocycles

• DOI: 10.1021/jacs.9b09330
• Publication Date: 2019-09-27T01:23:44Z
• Authors: Liu Leo Liu; Jiliang Zhou; Levy L. Cao; Douglas W. Stephan
• Keywords: Synthon

The phosphaaluminirenes HC[(CMe)(NDipp)]2Al[C(R)═P] (Dipp = 2,6-i-Pr2C6H3, R tBu or adamantyl) 2 and 3, featuring an unsaturated three-membered AlCP ring, have been synthesized as crystalline solids via a [1 + 2] cycloaddition reaction of the aluminum(I) complex HC[(CMe)(NDipp)]2Al (1) with phosphaalkynes. Computational investigations infer three-centered 2π-electron aromaticity rings. Compound 3 is readily protonated by tBuOH to induce ring-opening σ-bond metathesis, giving alumina-substituted P-hydrogeno phosphaalkene 4. Remarkably, high strain ring allows for facile enlargement in reactions CyNC, bis(diisopropylamino) cyclopropenylidene (BAC), elemental Se, Ph2CO, PhCH═CHCOPh, PhCN at room temperature. These furnish series unprecedented main group heterocycles 5-10 C═P bonds remaining intact. mechanisms are considered light thorough density functional theory (DFT) calculations.