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. 2013 Oct 16;18(10):12820-44.
doi: 10.3390/molecules181012820.

Synthesis of cycloveratrylene macrocycles and benzyl oligomers catalysed by bentonite under microwave/infrared and solvent-free conditions

René Miranda  1 , Omar Valencia-Vázquez, Carlos Abel Maya-Vega, Inés Nicolás-Vázquez, Yolanda Marina Vargas-Rodriguez, José Antonio Morales-Serna, Eréndira García-Ríos, Manuel Salmón
Affiliations

Synthesis of cycloveratrylene macrocycles and benzyl oligomers catalysed by bentonite under microwave/infrared and solvent-free conditions

René Miranda et al. Molecules. .

Abstract

Tonsil Actisil FF, which is a commercial bentonitic clay, promotes the formation of cycloveratrylene macrocycles and benzyl oligomers from the corresponding benzyl alcohols in good yields under microwave heating and infrared irradiation in the absence of solvent in both cases. The catalytic reaction is sensitive to the type of substituent on the aromatic ring. Thus, when benzyl alcohol was substituted with a methylenedioxy, two methoxy or three methoxy groups, a cyclooligomerisation process was induced. Unsubstituted, methyl and methoxy benzyl alcohols yielded linear oligomers. In addition, computational chemistry calculations were performed to establish a validated mechanistic pathway to explain the growth of the obtained linear oligomers.

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Figures

Figure 1
Figure 1
Conformers of benzyl alcohol.
Figure 2
Figure 2
Optimised structures obtained at the B3LYP/6-311G(d,p) level.
Figure 3
Figure 3
Sketch of B3LYP/6-311G(d,p) calculated energies HOMO, LUMO levels.
Figure 4
Figure 4
The highest occupied and lowest unoccupied molecular orbitals.
Figure 5
Figure 5
Optimised structures obtained at the B3LYP/6-311G(d,p) level.
Scheme 1
Scheme 1
Proposed reaction mechanism for the oligomerisation process.
See this image and copyright information in PMC

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