Synthesis of a New α-Azidomethyl Styrene from Safrole via a Dearomative Rearrangement

Abstract

There is a growing interest in developing more efficient synthetic alternatives for the synthesis of nitrogen-containing allylic compounds. This article presents a straightforward two-step protocol to produce 5-(3-azidoprop-1-en-2-yl)benzo[d][1,3]dioxole 4 from the natural product safrole. The method yielded the expected α-azidomethyl styrene 4, in good yield, via a dearomative rearrangement.

Quantum Chemical Insight into 1,2-Shift Rearrangement in Bromination of Allylaryls

“…Recently, we reported the synthesis of α-alkyl styrene using transition metal-free one-pot reaction conducted under mild conditions. − Interestingly, this reaction resulted in a mixture of two distinct styrene derivatives, a and b (Scheme ). Based on the experimental observations in our previously reported work and the bromine-mediated rearrangement reaction studies done by Dubois and Costa, it was proposed that allylaryl undergoes an alkene bromination to form bromonium intermediate I , which later on undergoes an intramolecular rearrangement, a 1,2-shift by the electron-rich aryl moiety to form the spiro[2.5] intermediate II . , The spiro[2.5] intermediate II can be ring-opened by a nucleophilic attack by a Br – anion on the three-membered ring to produce either a 2,3-dibromo derivative ( a ) or a 1,3-dibromo derivative ( b ).…”