methodology for the C(sp3)−C(sp3) functionalisation of saturated N-heterocyclic systems is disclosed. First, aminal derivatives are generated through the anodic oxidation of readily accessible carboxylic acids. Then, in the presence of BF3 ⋅ OEt2, iminium ions are unmasked and rapidly alkylated by organozinc reagents under flow conditions. Secondary, tertiary and quaternary carbon centers have been successfully
Convenient Procedure for the Indium-Mediated Hydroxymethylation of Active Bromo Compounds: Transformation of Ketones into α-Hydroxymethyl Nitroalkanes
作者:Raquel Soengas、Amalia Estévez
DOI:10.1055/s-0030-1258581
日期:2010.10
gaseous formaldehyde is described. Moreover, under these conditions, bromonitroalkanes were converted into the corresponding α-monohydroxymethylated nitroalkanes, which are precursors of the corresponding α-amino acids. Considering the easy transformation of ketones into bromonitroalkanes, this represents a method for the formal synthesis of α-amino acids from ketones.
Radical and Cation Crossover Reaction System Enables Synthesis of Complex Aliphatic Chains Possessing Functionalized Quaternary Carbons
作者:Yumi Murata、Taisei Shimada、Takashi Nishikata
DOI:10.1246/bcsj.20190120
日期:2019.9.15
Controlling the reactive species during the synthesis of complex aliphatic chains containing a quaternary carbon is incredibly difficult. In this paper, we efficiently controlled both radical and c...
Formation of quaternary carbons through cobalt-catalyzed C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Negishi cross-coupling
作者:Eduardo Palao、Enol López、Iván Torres-Moya、Antonio de la Hoz、Ángel Díaz-Ortiz、Jesús Alcázar
DOI:10.1039/d0cc02734k
日期:——
quaternary carbons is a key challenge in organic and medicinal chemistry. We report a cobalt-catalyzed C(sp3)–C(sp3) cross-coupling that allows for the introduction of benzyl, heteroarylmethylzinc and allyl groups to halo-carbonyl substrates. The cross-coupling reaction is selective for C(sp3)-over C(sp2)-halides, in contrast to most used catalytic metals, and allows access to novel scaffolds of pharmaceutical
Herein, we report an efficient method for the tertiary alkylation of a ketone by using an α‐bromocarbonyl compound as the tertiary alkyl source in a combined Cu‐organocatalyst system. This dual catalyst system enables the addition of a tertiary alkyl radical to an enamine. Mechanistic studies revealed that the catalytically generated enamine is a key intermediate in the catalytic cycle. The developed