Functional group manoeuvring for tuning stability and reactivity: synthesis of cicerfuran, moracins (D, E, M) and chromene-fused benzofuran-based natural products.

The protecting group manoeuvring as a strategy was applied for tuning the stability and reactivity of 4-(2,2-dibromovinyl)benzene-1,3-diol (12a) and 6-(2,2-dibromovinyl)-2,2-dimethylchroman-7-ol (22) in the domino synthesis of benzofuran-based natural products (1-8). The functional group demands and their impact on the reactivity driven by electronic effects were successfully managed by varying the protecting groups with substituted gem-dibromovinylphenols in domino couplings and triarylbismuth reagents under palladium-catalyzed conditions. This approach paved the way for the synthesis of moracin M (1) and cicerfuran (2), and the first time synthesis of moracin D (3) and moracin E (4) along with chromene-fused benzofuran-based natural products (5-8) in overall good yields.

Rapid regio- and multi-coupling reactivity of 2,3-dibromobenzofurans with atom-economic triarylbismuths under palladium catalysis.

A regio- and chemoselective cross-coupling study using 2,3-dibromobenzofurans and 2,3,5-tribromobenzofuran was achieved with sub-stoichiometric loadings of triarylbismuths as atom-economic reagents under Pd-catalyzed conditions. As part of this study, various 2,3-diaryl- and 2,3,5-triarylbenzofuran products were obtained in high yields, involving one-pot operations and short reaction times.