Executive Summary : | Annulations represent a most reliable tool for orchestrating multi-cyclic motifs in shorter and convenient pathways. On the other hand, the development of transition metal catalyzed C-H activation reactions changed the way of designing and synthesizing complex molecules in astonishingly shorter routes. The unterminated directing group is often not wanted at the product end and thus raises the concern. The constructive side of the coin opens avenues for annulations combining C-H and DG as two terminals of the partner. This tactic eventually shaped the repertoire of C-H functionalizations with efficient and sustainable transformations. Regardless, due to soaring documented effectiveness of these methods in organic synthesis, it is coherent that more pragmatic and universal approaches are highly sought-after. In this regard, installing a reactive DG in a coupling partner could provide comprehensive solutions through forming a bidirectional platform for Regioselective double annulations. This reactive DGs not only directs the effective regioselection, but also participate in reaction to produce divergent multicyclics. Over the past few years various coupling partners were employed in C-H activation. Use of alkyne as a coupling partner in C-H activations set the stage for modern diversification. However, these methods were mainly restricted to the use of symmetrical alkynes, and the regioisomeric issue with unsymmetrical alkynes significantly hamper the novelty of the method. Incorporating a DG in the alkynes could be a crucial tactic to address the regioselective issues. To this end, 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. We recently set our sights on harnessing the reactivity of PAs in C-H functionalizations, driven by the fact that they bespoke chameleon reactivity to give entry into complex motifs. Study of co-ordination capability of various groups at different distances is the initial subject of our project. The impact of various co-ordinating groups on reactivity, regioselectivity and tandem modifications will be extensively studied. Thus, Bi-directional double oxidative dual annulations, dual annulations of 1,3-diynes bearing a DG at one end, dual annulation of DG centered 1,6-enynes, sequential cyclization of 2,2-difunctionalized diphenyl acetylene and consecutive/regioselective insertion of functionalized alkynes, electrophilic cyclization & C-H functionalization of o-substituted diphenyl acetylenes, homo Propargylic systems, ynone oxime ethers for consecutive/regioselective insertion of functionalized alkynes will be studied in depth. Application of the achieved annulations for the shorter pathways to natural products and bioactive molecules will be entailed. |