Drawing from a Pool of Radicals for the Design of Selective Enyne Cyclizations
摘要:
Despite the possibility of intermolecular attack at four different locations, the Bu3Sn-mediated radical cyclization of aromatic enynes is surprisingly selective. The observed reaction path originates from the least stable of the equilibrating pool of isomeric radicals produced by intermolecular Bu3Sn attack at the pi-bonds of substrates. The radical pool components are kinetically self-sorted via 5-exo-trig closure, the fastest of the four possible cyclizations. The resulting Sn-substituted indenes are capable of further transformations in reactions with electrophiles.
Expedient and Divergent Tandem One-Pot Synthesis of Benz[<i>e</i>]indole and Spiro[indene-1,3′-pyrrole] Derivatives from Alkyne-Tethered Chalcones/Cinnamates and TosMIC
An efficient solvent-dependent regioselective [3 + 2]-cycloaddition/iodocyclization cascade reaction of alkyne-tethered chalcones/cinnamates and TosMIC has been developed. The reaction represents a novel protocol for the expedient and divergent one-pot synthesis of benz[e]indoles and spiro[indene-1,3′-pyrroles] from acyclic common precursors at room temperature.
已经开发了一种有效的溶剂依赖的炔烃系查耳酮/肉桂酸酯和TosMIC的区域选择性[3 + 2]-环加成/碘环化级联反应。该反应代表了在室温下由非环状常见前体方便,多样地合成苯并[ e ]吲哚和螺[indene-1,3'-吡咯]的新颖方法。