Rhodium-catalysed homo-coupling of terminal alkynes: divergent synthesis of bioactive 1,3-diynes and conjugated enediynes

Abstract

C(sp)–C(sp) cross-coupling of terminal alkynes represents a robust tool for building biologically active 1,3-diynes although confronted with huge challenges regarding selectivity control. Herein, a unique rhodium-catalysed homo-coupling of aromatic terminal alkynes has been achieved, enabling diversity-oriented synthesis (DOS) of 1,3-diynes and conjugated enediynes with high selectivity. Notably, both symmetrical and unsymmetrical 1,3-diynes have been prepared in good yields under mild reaction conditions with wide substrate scope and excellent functional group compatibility. Gratifyingly, further biological evaluation disclosed that the conjugated enediynes exhibited good inhibitory activities against several cancer cell lines. Moreover, 1,3-diyne 2a could effectively inhibit ferroptosis with sub-micromolar activity (EC₅₀ = 114 nM in HT-1080 cell).