DBU- and DABCO-Promoted Selective Access to 2,5-Diarylnitrobenzoates and Cyclohexenones via One-Pot Reactions

Abstract

Remarkable organobase-controlled selective synthesis of a wide breadth of valuable 2,5-diaryl-4-nitrobenzoates and 1-hydroxy-4- oxocyclohexencarboxylates bearing a tetrasubstituted stereogenic carbon is reported. This one-pot cyclization reaction operates between a bunch of 3-nitroallylarenes and unsaturated -ketocarbonyls by carefully choosing DBU or DABCO as an organobase under aerobic conditions. Notably, as a nucleophilic base, DABCO favors the Nef reaction over the dehydration aerial oxidation process, aiming for unexpected cyclohexanone architectures. Moreover, this operationally simple technique holds a few positive qualities: good yields with diastereoselectivities (dr 91:9), broad substrate scope, no added oxidant, excellent functional group compatibility, 100% carbon-economical, etc. Furthermore, the obtained 4-nitrobenzoate framework has been utilized for the synthesis of a range of valuable compounds such as 2-phenylcarbazole- 3-carboxylate, 3-bromoaniline derivative, and 2,5-diphenylbenzoic acid, among others. © 2022 Georg Thieme Verlag. All rights reserved.