The impact of Lewis acid variation on reactions with di-tert-butyl diazo diesters

Abstract

Reactions of (tBuO₂CN)₂ with Lewis acids and FLPs have previously been shown to prompt the formation of diazene compounds. In this work, we show that the reaction of (tBuO₂CN)₂ with 9-BBN leads to a bicyclic heterocyclic product (tBuOCO(BBN)CN)₂1. In contrast, the reactions of (tBuO₂CN)₂ with BF₃ or [Et₃Si][B(C₆F₅)₄] lead to the isolation of [tBuNHNH₂tBu][BF₄] 2 and [tBuN(H)NtBu][B(C₆F₅)₄] 3, respectively. The mechanism for the formation of 2 is probed computationally, demonstrating that steric and electronic considerations of the Lewis acid impact the reaction pathway.