Executive Summary : | Annulations are a reliable tool for orchestrating multi-cyclic motifs in shorter and convenient pathways. Transition metal-catalyzed C-H activation reactions have changed the way of designing and synthesizing complex molecules in astonishingly shorter routes. However, the unterminated directing group is often not wanted at the product end, raising concerns. The constructive side of the coin opens avenues for annulations combining C-H and DG as two terminals of the partner, shaping the repertoire of C-H functionalizations with efficient and sustainable transformations. Reactive DGs in a coupling partner could provide comprehensive solutions through forming a bidirectional platform for Regioselective double annulations. These reactive DGs not only direct effective regioselection but also participate in reaction to produce divergent multicyclics. Propargylic alcohols (PA) offer aptitude to organize metallacycle framework through an immediate coordination of transition metal with hydroxyl group as well as alkyne, resulting in structurally heterogeneous cascade outcomes with high chemo and regioselectivities.
The study aims to harness the reactivity of PAs in C-H functionalizations, driven by their bespoke chameleon reactivity to give entry into complex motifs. The impact of various co-ordinating groups on reactivity, regioselectivity, and tandem modifications will be extensively studied. Various annulations, such as bi-directional double oxidative dual annulations, dual annulations of 1,3-diynes bearing a DG at one end, dual annulations of DG-centered 1,6-enynes, sequential cyclization of 2,2′-difunctionalized diphenyl acetylene, electrophilic cyclization & C-H functionalization of o-substituted diphenyl acetylenes, homo Propargylic systems, and ynone oxime ethers for consecutive/regioselective insertion of functionalized alkynes, will be studied in depth. |