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Functionalized 1,4-naphthoquinones have been employed as versatile synthons in organic synthesis, in addition to presenting a large array of biological activities. Herein, the applications of 2-amino-/ acetylamino-substituted 3-iodo-1,4-naphthoquinones in cross-coupling reactions are described to successfully afford sixteen novel 3-styryl-1,4-naphthoquinones (amino-stilbene-quinone hybrids) and four 3-alkynyl-1,4-naphthoquinone in overall good yields. Interestingly, the alkynylated derivatives could be obtained from ligand- and Pd-free CuI-mediated cross-coupling reactions, after extensive investigations to exclude Pd as a co-catalyst. Lastly, the desilanized terminal alkyne was subjected to click chemistry reactions to give two novel triazole-1,4-naphthoquinone hybrids.

Styrenes were coupled with 3-iodolawsone in PEG-400 at 90 °C, leading stereoselectively to (E)-stilbene-quinone hybrids through Heck reactions. The best reaction conditions were found to be the use of NaOH (3 equiv) and 10 mol% of palladium acetate at 90 °C for 15 minutes. The chemical yields of the Heck reactions using styrenes with electron-withdrawing groups (65–98%) were greater than styrenes bearing electron-donating groups (7–32%) on the aromatic ring. In particular, the chemical yields of Heck reactions involving nitrostyrenes were the best ones observed.