Efficient synthesis of α,β-unsaturated alkylimines performed with allyl cations and azides: application to the synthesis of an ant venom alkaloid.

An efficient synthesis of α,β-unsaturated alkylimines at low temperature using azides has been developed. Carbocations generated from allyl alcohols helped achieve a rapid conversion under mild conditions with azides to afford reactive α,β-unsaturated imines. Hydroxy or alkoxy groups are essential for these transformations, and utilizing readily accessible allyl alcohols gave a wide extension of substrates. The efficiency of this novel method is demonstrated in the total synthesis of an iminium ant venom alkaloid.