Transition metal‐catalyzed [2+2+2] cyclotrimerization is a powerful method to synthesize substituted benzene derivatives with optimal atom efficiency. However, controlling regio‐ and chemoselectivity is difficult. We present a cobalt catalyzed cycloaddition of alkynes, which provides the cycloaddition products in high yields and excellent regioselectivity in the presence of a pyridine‐2,6‐diimine ligand
Synergistic Palladium-Catalyzed C(sp3)H Activation/C(sp3)O Bond Formation: A Direct, Step-Economical Route to Benzolactones
作者:Petr Novák、Arkaitz Correa、Joan Gallardo-Donaire、Ruben Martin
DOI:10.1002/anie.201105894
日期:2011.12.16
Simplified access: Substituted benzolactones can be obtained in one step by a Pd‐catalyzed ligand‐accelerated C(sp3)H bond‐activation/C(sp3)O bond‐formation protocol. This step‐economical approach enables the preparation of benzolactones with a wide variety of functional groups and different substitution patterns. The method is characterized by its simplicity and the avoidance of protecting groups
Ligand-Enabled Pd(II)-Catalyzed C(sp<sup>3</sup>)–H Lactonization Using Molecular Oxygen as Oxidant
作者:Shaoqun Qian、Zi-Qi Li、Minyan Li、Steven R. Wisniewski、Jennifer X. Qiao、Jeremy M. Richter、William R. Ewing、Martin D. Eastgate、Jason S. Chen、Jin-Quan Yu
DOI:10.1021/acs.orglett.0c01243
日期:2020.5.15
Pd(II)-catalyzed C-H lactonization of o-methyl benzoic acid substrates has been achieved using molecular oxygen as the oxidant. This finding provides a rare example of C-H oxygenation through Pd(II)/Pd(0) catalysis as well as a method to construct biologically important benzolactone scaffolds. The use of a gas mixture of 5% oxygen in nitrogen demonstrated the possibility for its application in pharmaceutical