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Abstract A protocol for the iterative decarboxylative cross‐coupling of carboxylic acids with dehydroalanine (Dha) allyl esters is described. A procedure for decarboxylative Giese addition to dehydroalanine allyl esters that avoids 5‐exo‐trig radical cyclization onto the allyl moiety was developed. This results in complex, substituted alanine allyl esters that are poised for a second decarboxylative coupling. Thus, following the photocatalytic decarboxylative alkylation of Dha, the resulting amino acid allyl esters were subjected to decarboxylative allylation under metallaphotoredox/palladium catalysis. The Giese addition and decarboxylative allylation can be performed in one pot simply by triggering the decarboxylative allylation by addition of a palladium catalyst. These one‐pot decarboxylative couplings leverage temporally controlled carboxylate formation to allow controlled, sequential photoredox activation of the carboxylates. The ability to perform sequential, one‐pot photoredox C─C bond formations obviates the need for isolation of intermediates. The final products of these coupling reactions are densely functionalized homoallylic amines and/or unsymmetric, differentiated 1,3‐diamines, both known for their high synthetic value. 

Abstract The rising demand and financial costs of noble transition metal catalysts have emphasized the need for sustainable catalytic approaches. Over the past few years, base‐metal catalysts have emerged as ideal candidates to replace their noble‐metal counterparts because of their abundance and easiness of handling. Despite the significant advancements achieved with precious transition metals, earth‐abundant cobalt catalysts have emerged as efficient alternatives for allylic substitution reactions. In this review, allylic alkylations at sp³‐carbon centers mediated by cobalt will be discussed, with a special focus on the mechanistic features, scope, and limitations. 

Abstract In recent years, there has been a concerted drive to develop methods that are greener and more sustainable. Being an earth‐abundant transition metal, cobalt offers an attractive substitute for commonly employed precious metal catalysts, though reactions engaging cobalt are still less developed. Herein, we report a method to achieve the decarboxylative allylation of nitrophenyl alkanes, nitroalkanes, and ketones employing cobalt. The reaction allows for the formation of various substituted allylated products in moderate‐excellent yields with a broad scope. Additionally, the synthetic potential of the methodology is demonstrated by the transformation of products into versatile heterocyclic motifs. Mechanistic studies revealed an in situ activation of the Co(II)/dppBz precatalyst by the carboxylate salt to generate a Co(I)‐species, which is presumed to be the active catalyst. 

Abstract A photoredox/cobalt dual catalytic procedure has been developed that allows benzoylation of olefins. Here the photoredox catalyst effects the decarboxylation of α‐ketoacids to form benzoyl radicals. After addition of this radical to styrenes, the cobalt catalyst abstracts a H‐atom. Hydrogen evolution from the putative cobalt hydride intermediate allows a Heck‐like aroylation without the need for a stoichiometric oxidant. Mechanistic studies reveal that electronically different styrenes lead to a curved Hammett plot, thus suggesting a change in product‐determining step in the catalytic mechanism.