Copper-Silver Dual Catalyzed Decyanative C-Se Cross-Coupling

摘要

Traditionally, a metal-catalyzed cross-coupling reaction is governed by displacement of leaving groups such as halogens, tosylates, etc. by different nucleophiles leading to the formation of carboncarbon and carbon-heteroatom bonds. Besides displacement of traditional leaving groups in coupling reactions decyanative cross-coupling has also received current attention. The objective of this work is to develop a decyanative cross-coupling through metal-assisted nucleophilic displacement, which is less explored so far. Thus, a decyanative cross-coupling of aryl selenocyanate with aryl-/alkylacetylenes, boronic acids and silanes has been accomplished by a copper-assisted nucleophilic displacement reaction for an easy access to a series of diaryl, aryl alkyl, aryl vinyl and aryl alkynyl selenides. The best yield of product was obtained using 5 mol% of Cu(OAc)(2), Ag2CO3 (20 mol%) and Cs2CO3 (1 equiv.) at 100 degrees C for 8 h in N-methylpyrrolidinone (NMP). The advantages of simple operation, high yields and general applicability make this procedure more attractive. A mechanistic pathway has been proposed. Silver plays a key role in the decyanation process. A plausible mechanistic pathway of this decyanative carbon-selenium cross-coupling has been proposed based on UV, EPR, HR-MS and IR analytical data along with results obtained from control experiments.