Prins cyclization between a homoallylic alcohol and an aldehyde, promoted by trimethylsilyl halide, afforded 4-halo-tetrahydropyrans with good to excellent yields. Thanks to the absence of the solvent and metal, the THP thus obtained have been implicated without purification in several other reactions, in a sequential way, affording in particular new indole derivatives.
Prins Cyclization Catalyzed by a Fe
<sup>III</sup>
/Trimethylsilyl Halide System: The Oxocarbenium Ion Pathway versus the [2+2] Cycloaddition
作者:Sixto J. Pérez、Martín Purino、Pedro O. Miranda、Víctor S. Martín、Israel Fernández、Juan I. Padrón
DOI:10.1002/chem.201502488
日期:2015.10.19
iron(III)‐catalyzed Prins cyclization reactionbetween homoallylic alcohols and non‐activatedalkenes, two mechanistic pathways can be envisaged, namely the classical oxocarbenium route and the alternative [2+2] cycloaddition‐based pathway. It is found that the [2+2] pathway is disfavored for those alcohols having non‐activated and non‐substitutedalkenes. In these cases, the classical pathway, via
A convenient method for the synthesis of 4,4-diarylbut-1-enes via the successive allylation of aromatic aldehydes and the Friedel–Crafts alkylation reaction of aromatic nucleophiles with the intermediary benzyl silyl ethers using HfCl4 or Cl2Si(OTf)2
The three-component coupling reaction among aromaticaldehydes, allyltrimethylsilane and aromatic nucleophiles is efficiently performed by the promotion of HfCl4. A similar reaction occurs using allyltributyltin as the first nucleophile to aromaticaldehydes with a catalytic amount of Cl2Si(OTf)2 generated in situ from SiCl4 and AgOTf.
Diastereoselective syntheses via Prins cyclization, crystal structures determination and theoretical studies of cis-2,6-diphenyl-4-hydroxytetrahydropyran and analogues
Abstract We report in this article the diastereoselective syntheses of tetrahydropyranyl derivatives 1–5, its cis configurational ascertainment by spectroscopy and finally the crystal structures determination that unequivocally shows the 1–5 configurations and its crystals packing features. Besides that, we have developed a theoretical study using density functional theory (M06-2X/6-311++G**) to obtain
The Role Ionic Liquid [BMIM][PF6] in One-Pot Synthesis of Tetrahydropyran Rings through Tandem Barbier–Prins Reaction
作者:Poliane K. Batista、João Marcos G. de O. Ferreira、Fabio P. L. Silva、Mario L. A. A Vasconcellos、Juliana A. Vale
DOI:10.3390/molecules24112084
日期:——
aldehydes. The use of [BMIM][PF6] gave Prins products from several aldehydes in good yields and reaction times. We also found that the anion, PF6-, accelerates the Barbier reaction when used alone, and the excess SnBr2 from the reaction conditions of the Barbier reaction leads to the formation of the THP rings, thus acting as a catalyst for Prinscyclization. Additionally, we demonstrate that ionic