New Hindered Amide Base for Aryne Insertion into Si–P, Si–S, Si–N, and C–C Bonds

A general method for a new, hindered
lithium diadamantylamide (LDAM)
base-promoted insertion of arynes into Si–P, Si–S, Si–N,
and C–C bonds is described. Arynes are generated from easily
available aryl triflates and halides. Subsequent reaction of the aryne
with silylated phosphines, sulfides, or amines affords the insertion
products. Furthermore, a one-step synthesis of anthracenes from aryl
halides and aryl ketones is also demonstrated. Cyano, aryl, alkyl,
trifluoromethyl, vinyl, methoxy, chloro, fluoro, and even formyl moieties
are compatible with the reaction conditions. The new lithium amide
affords higher yields compared with lithium tetramethylpiperidide
(LiTMP)-promoted reactions. Furthermore, the bulkiness of LDAM base
essentially suppresses aryne reaction with base, allowing use of aryl
halides and triflates as the limiting reagents.