Concise Synthesis of Chromene/Chromane-Type Aryne Precursors and Their Applications

The gram-scale synthesis of 5,6-, 6,7-, and 7,8-chromene/chromane-type aryne precursors and their applications in regioselective transformation to other functional derivatives is reported. Chromene/chromane-type arynes are generated under mild conditions, which can further undergo [2 + 2], [3 + 2], and [4 + 2] cycloaddition reactions, nucleophilic addition reactions, and a-insertion reactions to produce structurally novel substituted chromenes and chromanes. The excellent regioselectivity of the reaction is facilitated by the oxygen-containing guiding groups at the ortho-position of the triple bond, which can be removed or switched to other functional groups including alkenyl, aryl, heteroaryl, and arylamino groups.

Automated summary

In this study, gram-scale synthesis of 5,6-, 6,7-, and 7,8-chromene/chromane-type aryne precursors was reported, and their regioselective transformation to other functional derivatives was demonstrated. The reactions showed excellent regioselectivity facilitated by oxygen-containing guiding groups at the ortho-position of the triple bond, leading to structurally novel substituted chromenes and chromanes.