Tunable Dimerization and Trimerization of β-Alkynyl Ketones via Silver Catalysis for Accessing Spiro and Dispiro Compounds Containing 1H-Isochromene

Dan Wang,¹ Shuai Liu,¹ Xin-Chan Lan, Armando Paniagua, Wen-Juan Hao,^* Guigen Li, Shu-Jiang Tu,* Bo Jiang*

(¹共同一作)

New silver-catalyzed tunable dimerization and trimerization of b-alkynyl ketones have been established, enabling multiple C-C bond-forming events to selectively access skeletally diverse spiro isochromenes with generally good yields. The silver-enabled bicycloaddition of b-alkynyl ketones with water offered hydroxylated spiro isochromenes. Without water, spiro isochromenes with methylene moiety were obtained through catalytic 6-endo- digoxo-cyclization/[4+2] cycloaddition cascades by using pyridine as additives whereas employment of 1,1‘-binaphthyl-2,2‘-diyl hydrogen phosphate (BiNPO₄H) as a Brønsted acid catalyst rendered the unprecedented dispiro trimerization products through double C(sp³)-H functionalization.

Adv. Synth. Catal. 2017, 359, 3186-3193