Synthetic utility of tert-butyl azidoacetate on the Hemetsberger-Knittel reaction (synthetic studies of indoles and related compounds part 47)

Abstract

The synthetic utility of tert-butyl azidoacetate (7) on the Hemetsberger-Knittel reaction is described. The following two findings are disclosed by using tert-butyl azidoacetate (7): i) in the first step for the synthesis of ethyl indole-2-carboxylate 4, the aldol reaction of less reactive aldehydes 1a, b was improved greatly; ii) tert-butyl indole-2- carboxylate 10 becomes readily available from aldehydes.