Active pyrylium intermediates are in situ generated by a Rh-catalyzed vinylic C–H annulation reaction between exocyclic α,β-enones and alkynes, which undergo a base-promoted rearrangement via 1,5-H shift to form 1H-benzo[f]chromenederivatives.
活性吡啶鎓中间体是通过环外α,β-烯酮和炔烃之间的Rh催化乙烯基C–H环合反应原位生成的,环化反应通过1,5-H移位进行碱促进的重排,形成1 H-苯并[ f ] chromene衍生物。
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</sup>Bu<sub>4</sub>NPF<sub>6</sub> promoted regioselective cascade synthesis of functionally embellished naphthofurans under acid, metal & solvent free conditions
作者:Abhishek Pareek、Ravikrishna Dada、Monika Rana、Anuj K. Sharma、Srinivasarao Yaragorla
DOI:10.1039/c6ra17411f
日期:——
n Bu4NPF6 mediated highly regioselective synthesis of functionally embellished naphthofurans has been achieved from easily available naphthols and propargyl alcohols through a cascade benzylation, oxacyclisation (5-exo dig) and isomerization undersolventfreeconditions. The reaction works in a short time through dibenzyl ether formation followed by the decomposition to the carbocation to furnish