In situ formed acetal changes the course of Brønsted acid-catalyzed reaction of ortho-alkynylbenzaldehydes with arylalkynes altogether. By utilizing this, an efficient domino approach for the regioselective synthesis of substituted benzo[a]fluorenes has been developed under mild reaction conditions. In situ formed acetal facilitates the intermolecular heteroalkyne metathesis and subsequent trans to cis isomerization of a double bond to effect the intramolecular annulation.

Substituted arylethanols can be coupled by using a readily available Ru catalyst in a fully deoxygenative manner to produce hydrocarbon chains in one step. Control experiments indicate that the first deoxygenation occurs through an aldol condensation, whereas the second occurs through a base-induced net decarbonylation. This double deoxygenation enables further development in the use of alcohols as versatile and green alkylating reagents, as well as in other fields, such as deoxygenation and upgrading of overfunctionalized biomass to produce hydrocarbons.

Activation of the aci-form of nitromethane using Lewis acids for the attack of carbon nucleophiles was studied. 1,3-Dicarbonyl compounds in the presence of catalytic amounts of AuCl(3) or Cu(OTf)(2) in nitromethane solvent could be converted into methylene-bridged bis-1,3-dicarbonyl compounds.

An interesting domino reaction for the synthesis of substituted naphthyl ketones has been developed using readily accessible starting materials. This domino reaction proceeds via in situ incorporation of an acetal followed by intramolecular heteroalkyne metathesis/annulation in an ortho-alkynylacetophenone derivative. A deuterium incorporation experiment has been carried out to understand the mechanism.

Iridium(III)-pyridone complexes are commonly found to react in a cooperative and redox-neutral manner with dihydrogen and alcohols. In this work, the reactivity preferences of Ir I -pyridone complexes were investigated under a variety of conditions. We have found that, in contrast to Ir III -pyridones, Ir Ipyridone complexes display a strong preference to react noncooperatively. With a new chelating 2-hydroxy-8-diphenylphos- [a]

Using the in‐situ‐formed acetal strategy, a facile approach has been developed to synthesize naphthalene derivatives from o‐alkynylbenzaldehydes and enolizable ketones. In situ acetal formation assists the condensation between o‐alkynylbenzaldehydes and enolizable ketones to give chalcone derivatives under Brønsted acidic conditions. In situ acetal formation facilitates the reaction by increasing the electrophilicity of the carbonyl carbon of the o‐alkynylaldehyde through oxonium ion formation, and also by enhancing the nucleophilicity of the α carbon of the ketone through the formation of an enol ether. The formed chalcones undergo trans to cis isomerization to effect alkyne–carbonyl metathesis to give naphthalene derivatives.

2H‐Chromene is an important structural motif present in many biologically active compounds, natural products and showed many other properties. Deep Eutectic Solvent (DES) an environmentally benign and alternative to the conventional organic volatile solvents has been utilized first time for the synthesis of the 2H‐chromene derivatives in moderated to excellent yields. The DES is recycled for 5 times for the synthesis of 2H‐chromene derivatives. Based on the stability of ring size, we justified the regio‐selectivity on the formation of cyclization product. Based on the control experiments, we ruled out the free radical mechanism and propose the ACM mechanistic path to construct chromene skeleton.

A new protocol has been developed for the synthesis of indene derivatives in a diastereoselective manner from o-alkenylbenzaldehydes and enolizable ketones in the presence of trimethyl orthoformate and catalytic triflic acid. This method involves tandem in situ formed acetal-assisted Claisen-Schmidt condensation followed by 5-exo-trig cyclization/Michael addition in one-pot. It has also been shown that the chalcones derived from o-alkenylbenzaldehydes and ketones can effectively be transformed into indene derivatives in the presence of TfOH catalyst alone.