A novel etherification of 2-hydroxy-1,4-naphthoquinone derivatives with alkoxyalkyl chlorides and hydride bases is described. Precise study of the conditions and substrate scope suggested that the reaction occurs specifically in the molecule having a 2-hydroxy-1,4-benzoquinone skeleton. A chemoselective O-methylation reaction was achieved to afford a synthetically important intermediate, which offered easy access to a natural product possessing anti-tumor activity.

Described here is the first enantioselective total synthesis of lantalucratin C, which was isolated from the rainforest plant Lantana involucrata, and which possesses anti-tumor activity. The OH group on the aromatic ring was systematically introduced by an appropriate management of the OH protecting groups. The alkyl side chain connected to a chiral carbon center was incorporated by directed ortho-lithiation of naphthalenes followed by asymmetric epoxidation. The furano-1,2-naphthoquinone skeleton was constructed from 3-hydroxyalkylnaphthalene by CAN-mediated oxidative cyclization. The absolute stereochemistry at the C2 carbon was assigned the R-configuration by the Kusumi–Mosher method.

A concise method has been developed for the synthesis of caroverine and its derivatives. The quinoxalinone scaffold of these compounds was constructed via the tandem nitrosation/aerobic oxidative CN bond formation reaction of N-(2-chloroethyl)-2-cyano-N-phenylacetamide, followed by sequential Grignard, Finkelstein and nucleophilic substitutions reactions to give several different derivatives. Herein, we describe the development of this strategy in terms of the optimization of each step as well as the effect of different additives on the individual reactions.

An efficient method for constructing quinoxalinone-N-oxides from cyanoacetanilides has been developed. This transformation can be achieved using inexpensive reagents and molecular oxygen under mild conditions, thus offering a practical pathway to quinoxalinone-containing pharmaceuticals such as ataquimast and opaviraline.

Starting from a reduced lapachol compound, the total synthesis of rhinacanthin A in both racemic and enantioenriched forms is achieved in eight steps without forming any undesired β-lapachone derivatives. For the synthesis of enantioenriched rhinacanthin A, the introduction of the asymmetric center was carried out by using the catalytic asymmetric epoxidation of an unfunctional trisubstituted olefin using Shi’s epoxidation diketal catalyst. The acidic treatment of a derived enantioenriched epoxynaphthol and the following CAN oxidation afforded the target molecule with high enantiomeric purity.2-tert-Butyldimethylsilyloxy-1,4-dimethoxy-3-((3,3-dimethyloxiran-2-yl)methyl)naphthaleneC23H34O4SiEe = 83%[α]D24=-10.8 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)(R)-3,4-Dihydro-3-hydroxy-5,10-dimethoxy-2,2-dimethyl-2H-naphtho[2,3-b]pyranC17H20O4Ee = 83%[α]D24=-6.1 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)(R)-3,4-Dihydro-3-hydroxy-5,10-2,2-dimethyl-2H-naphtho[2,3-b]pyran-5,10-dione (rhinacanthin A)C15H14O4Ee = 82%[α]D24=-14.0 (c 1.0, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R)