Co-Catalyzed Suzuki-Miyaura Coupling of Organoboronic Acids and Alkynyl Chlorides Using Potassium Bicarbonate as Base

Organoboronic acids, some of the most common and widely used organoboron compounds, have not yet been used in the cobalt-catalyzed cross coupling reactions, despite cobalt demonstrating good reactivity with zinc reagents, Grignard reagents, and metal organoborates that are formed by n-butyl lithium or alkaline metal alkoxide salts and organoboron esters. Herein, a highly efficient and practical cobalt-catalyzed coupling reaction of aryl/alkenyl boronic acids and alkynyl chloride under mild reaction conditions is reported. The advantages of the organoboronic acids, along with a broad functional group compatibility and the reaction's tolerance to moisture and air, enable this reaction to be a synthetically useful protocol for the construction of a C(sp2)-C(sp) bond. Lastly, the synthesis of two natural products and a key intermediate of roxadustat was effectively accomplished using the methodology to construct the critical alkynyl-aryl bond.

Palladium-catalyzed cross-coupling of arylcarboxylic acid 2-pyridyl esters with terminal alkynes

In the presence of Na2CO3, the combination of PdCl2(dppf), dppp and CuI catalyzes the decarbonylative coupling of arylcarboxylic acid 2-pyridyl esters with terminal alkynes to afford 1,2-disubstituted acetylenes. (Hetero)aryl, alkyl, and silylacetylenes and various electron-donating and -withdrawing group-substituted arylcarboxylic acid 2-pyridyl esters can be used in this transformation, with a range of functional groups showing compatibility.

“Anti-Michael addition” of Grignard reagents to sulfonylacetylenes: synthesis of alkynes

The addition of Grignard reagents to arylsulfonylacetylenes, which undergoes an “anti-Michael addition”, resulting in their alkynylation under very mild conditions is described.

Iron-Catalyzed C-C Cross-Couplings Using Organometallics

Over the last decades, iron-catalyzed cross-couplings have emerged as an important tool for the formation of C-C bonds. A wide variety of alkenyl, aryl, and alkyl (pseudo)halides have been coupled to organometallic reagents, the most currently used being Grignard reagents. Particular attention has been devoted to the development of iron catalysts for the functionalization of alkyl halides that are generally challenging substrates in classical cross-couplings. The high functional group tolerance of iron-catalyzed cross-couplings has encouraged organic chemists to use them in the synthesis of bioactive compounds. Even if some points remain obscure, numerous studies have been carried out to investigate the mechanism of iron-catalyzed cross-coupling and several hypotheses have been proposed.

Recent advances in iron-catalysed cross coupling reactions and their mechanistic underpinning

Advances in iron-catalysed cross coupling from 2010–2015 are critically reviewed.

Coupling of α,α-difluoro-substituted organozinc reagents with 1-bromoalkynes

α,α-Difluoro-substituted organozinc reagents generated from conventional organozinc compounds and difluorocarbene couple with 1-bromoalkynes affording gem-difluorinated alkynes. The cross-coupling proceeds in the presence of catalytic amounts of copper iodide in dimethylformamide under ligand-free conditions.

Iron-promoted C-C bond formation in the total synthesis of natural products and drugs

Iron salts are inexpensive and almost innocuous; they are thus the promoters of choice, even in stoichiometric amounts, for the formation of carbon-carbon bonds in the backbone of complex molecules. This review encompasses the key role of iron complexes in the total synthesis of some natural products or pharmacologically important compounds.