zirconium‐mediated double homologation method was successfully applied for the synthesis of multi‐substitutedpentacenederivatives from 1,2,4,5‐tetrakis(propargyl)benzenes. The bis(zirconacyclopentadiene) intermediates were also characterized. Among these symmetrical derivatives, tetra‐ and octa‐substitutedpentacenes undergo reversible conversion between monomeric and dimeric forms.
Three-Step Synthesis of End-Substituted Pentacenes
作者:Matthew T. Stone、Harry L. Anderson
DOI:10.1021/jo7017284
日期:2007.12.1
[GRAPHICS]A concise, three-step synthesis of 1,4,8, 11 -substituted 2,3,9,10-tetrakis(methoxycarbonyl)pentacenes from commercially available 1,2,4,5-tetrakis(bromomethyl)benzene was established. Efficient alkynylation, followed by formation of four fused rings via a zirconacyclopentadiene intermediate, and then oxidation with DDQ gave pentacenes la-c. The process was compatible with methyl, phenyl, and trimethylsilyl substituents, which have good solubility in various organic solvents.