Selective reduction of aromatic azides in solution/solid-phase and resin cleavage by employing BF3•OEt2/EtSH.: Preparation of DC-81

An efficient method for the reduction of aromatic azides in both solution and solid-phase has been developed by employing (BF3OEt2)-O-./EtSH. This report also describes resin cleavage employing this reagent system. Further, this protocol has been utilized for the solution as well as the solid-phase synthesis of pyrrolo[2, 1-c][1,4]benzodiazepines, including the naturally occurring antibiotic DC-81 and fused [2,1-b]quinazolinones. (c) 2006 Elsevier Ltd. All rights reserved.