An efficient and transition-metal-free three-component reaction with benzynes formed in situ from 2-(trimethylsilyl)aryl triflate, phosphites, and ketones was developed for the synthesis of benzoxaphosphole 1-oxides. An array of benzoxaphosphole 1-oxides were prepared from both activated and non-activated ketones in moderate to good yields with a broad functional group tolerance. This reaction is useful for preparing organophosphorus compounds encountered in natural products and materials.