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Rh-Catalyzed Alkylation and Alkynylation of 1 with -Diazo- -keto Esters, -Diazo Esters, -D... In general, all reactions were carried out employing 50 mg of B 1 b . Rh catalysis, C-H activation, cross dehydrogenative coupling, GBT-440, diazo ester, TIPS-EBX In the context of developing new analogues of the GBT-440, one of our initial objectives was replacing the hydroxymethyl ether (which connects the pyridine and salicylaldehyde cores) with an olefin or a keto ester by pyrazole-directed C-H activation on the pyridine ring (Scheme 1, eq. 1). Keywords: Rh catalysis; C-H activation; cross dehydrogenative coupling; GBT-440; diazo ester; TIPS-EBX EN Rh catalysis C-H activation cross dehydrogenative coupling GBT-440 diazo ester TIPS-EBX 3600 3609 10 10/19/23 20231102 NES 231102 Graph Heterocyclic scaffolds like pyridine and pyrazole are the most privileged scaffolds present in many drug molecules. [Extracted from the article]

Herein, we describe an Au-catalyzed cycloisomerization process of a nitroalkyne that was projected to construct the central 2,2-disubstituted pseudoindoxyl core of the natural product Austamide. Our intended strategy for forging the pseudoindoxyl core is based on the nitroalkyne cycloisomerization followed by a subsequent intramolecular [3 + 2] cycloaddition. However, the [3 + 2] cycloaddition occurred in an undesired manner, ultimately leading to a complex hexacyclic scaffold. • Austamide. • Pseudoindoxyl natural product. • Gold catalysis. • Nitroalkyne cycloisomerization. • Intramolecular [3 + 2] cycloaddition. [ABSTRACT FROM AUTHOR]

The gold‐catalysed intramolecular redox cyclization of o‐alkynylnitrobenzens documented by Professors Naoki Asao and Yoshinori Yamamoto is an important discovery that has opened two complementary research domains. Advancing this cyclization with other metals as well as developing new methods around the products that result from this reaction is one aspect that has seen growing interest. On the other hand, the idea of generating α‐oxo gold carbenes via oxygen transfer to alkynes has established another important aspect in gold‐catalysis. In this account, we will be dealing with the first aspect, which revolves around the internal redox cyclization of nitroalkynes (trivially called as nitroalkyne cycloisomerization), focusing mainly on the gold‐complexes and the synthetic methods developed around it from our group and from other groups, and also providing the details of similar transformations documented with other metals so that the complementary reactivity/diversity of these transformations could be appreciated. [ABSTRACT FROM AUTHOR]