ABSTRACT
Trivalent group-9 metal catalysts with a cyclopentadienyl-type ligand (CpMIII ; M=Co, Rh, Ir, Cp=cyclopentadienyl) have been widely used for directed C-H functionalizations, albeit that their application to challenging C(sp3 )-H functionalizations suffers from the limitations of the available directing groups. In this report, we describe directed C(sp3 )-H amidation reactions of simple amide substrates with a variety of substituents. The combination of an electron-deficient CpE Rh catalyst (CpE =1,3-bis(ethoxycarbonyl)-substituted Cp) and an electron-deficient 2-pyridone ligand is essential for high reactivity.
ABSTRACT
Among sulfoximine derivatives containing a chiral sulfur center, benzothiadiazine-1-oxides are important for applications in medicinal chemistry. Here, we report that the combination of an achiral cobalt(III) catalyst and a pseudo-C2 -symmetric H8 -binaphthyl chiral carboxylic acid enables the asymmetric synthesis of benzothiadiazine-1-oxides from sulfoximines and dioxazolones via enantioselective C-H bond cleavage. With the optimized protocol, benzothiadiazine-1-oxides with several functional groups can be accessed with high enantioselectivity.
Subject(s)
Cobalt , Oxides , Benzothiadiazines/chemistry , Carboxylic Acids , Catalysis , Molecular Structure , Oxides/chemistry , StereoisomerismABSTRACT
Reported is an achiral Cpx RhIII /chiral carboxylic acid catalyzed asymmetric C-H alkylation of diarylmethanamines with a diazomalonate, followed by cyclization and decarboxylation to afford 1,4-dihydroisoquinolin-3(2H)-one. Secondary alkylamines as well as nonprotected primary alkylamines underwent the transformation with high enantioselectivities (up to 98.5:1.5 e.r.) by using a newly developed chiral carboxylic acid as the sole source of chirality to achieve enantioselective C-H cleavage by a concerted metalation-deprotonation mechanism.
