Surisetti Suresh

Gold-Catalyzed Intramolecular Cyclization of N-Propargylic β-Enaminones for the Synthesis of 1,4-Oxazepine Derivatives.

An efficient and mild one-pot, gold-catalyzed intramolecular cyclization of N-propargylic β-enaminones has been achieved for the generation of 1,4-oxazepine derivatives. This synthetic transformation tolerates a range of substituted N-propargylic β-enaminones in moderate to good yields.

Gold-catalysed cyclisation of N-propargylic β-enaminones to form 3-methylene-1-pyrroline derivatives.

A gold(I) catalysed reaction between N-propargylic β-enaminones and arynes was developed to access 3-methylene-1-pyrrolines. The title compounds were obtained in 57-78% yields. This reaction is useful for the generation of substituted 1-pyrrolines exhibiting significant molecular complexity.

Reaction of N-propargylic β-enaminones with acetylene dicarboxylates: catalyst-free synthesis of 3-azabicyclo[4.1.0]hepta-2,4-dienes

3-Azabicyclo[4.1.0]hepta-2,4-dienes were efficiently synthesized in a reaction of N-propargylic β-enaminones with acetylenedicarboxylates under novel and exceptional catalyst- and base-free conditions in a single step.

Copper-Catalyzed Tandem O-Arylation–Oxidative Cross Coupling: Synthesis of Chromone Fused Pyrazoles

Intermolecular tandem copper-catalyzed O-arylation-oxidative acylation (cross dehydrogenative coupling-CDC) has been developed under air as an oxidant. The reaction between 2,4-dihydro-3H-pyrazol-3-ones and ortho-halo aryl carboxaldehydes furnished the corresponding chromone fused pyrazoles, in a straightforward manner. The synthetic utility of the presented tandem catalysis has been demonstrated with the synthesis of an A2-subtype selective adenosine receptor antagonist in only two steps.

Ruthenium Phosphine-Pyridone Catalyzed Cross Coupling of Alcohols to form α-Alkylated Ketones

An efficient and green route to access diverse functionalized ketones via dehydrogenative-dehydrative cross-coupling of primary and secondary alcohols is demonstrated. Selective and tunable formation of ketones or alcohols is catalyzed by a recently developed proton responsive ruthenium phosphine-pyridone complex. Light alcohols such as ethanol could be used as alkylating agents in this methodology. Moreover, selective tandem double alkylation of isopropanol is achieved by sequential addition of different alcohols.

Tandem Aza Michael Addition–Vinylogous Nitroaldol Condensation: Construction of Highly Substituted N-Fused 3-Nitropyrazolopyridines

A base-mediated tandem aza-Michael addition-vinylogous nitroaldol condensation has been described between 3,5-dialkyl 4-nitropyrazoles and alkynyl ketones/aldehydes. This transition metal-free atom economical transformation occurred via C-N and C═C bond formations in one step with the elimination of water. The construction of a variety of highly substituted N-fused 3-nitropyrazolopyridine derivatives has been demonstrated with good yields. Good to excellent regioselectivities have been achieved with unsymmetrically substituted 4-nitropyrazoles.