One-Pot Synthesis of α-Amino Bisphosphonates from Nitriles via TfO/HC(OR)-Mediated Interrupted Ritter-Type Reaction.

A versatile synthesis of α-amino bisphosphonates has been achieved through one-pot interrupted Ritter-type reaction under mild conditions. The reactive Ritter intermediate nitrilium is generated by treatment of nitrile with readily accessible TfO/HC(OR), which is trapped by phosphite ester to deliver the desired product. This protocol is efficient, scalable, and well compatible with a broad scope of substrates.

TfO-Mediated Cyclization of 7-Enamides: Bioinspired Construction of Fused Eight-Membered Carbocyclic Enimines and Enones.

In this paper, we document the construction of functionalized and fused eight-membered carbocycles by the triflic anhydride-mediated cyclization of 7-enamides. Taking advantage of the high electrophilicity of the nitrilium ion intermediates, generated in situ from secondary -(2,6-dimethyl)anilides, the nonactivated, trisubstituted alkene-nitrilium cyclization reactions proceeded smoothly to afford nonconjugated β,γ-enimines (for fused 6/6/8 ring systems), conjugated α,β-enimines (for 6/5/8), or fused 5/8 ring systems in good yields. When the cyclization reactions were followed by one-pot acidic hydrolysis, the reaction led directly to the corresponding α,β-enones.