Polar tagging in the synthesis of monodisperse oligo(p-phenyleneethynylene)s and an update on the synthesis of oligoPPEs

• Dhananjaya Sahoo,
• Susanne Thiele,
• Miriam Schulte,
• Navid Ramezanian and
• Adelheid Godt

Beilstein J. Org. Chem. 2010, 6, No. 57, doi:10.3762/bjoc.6.57

• better than (highly) activated MnO2. The use of HOM as an alkyne protecting group is accompanied by carbometalation as a side reaction in the alkynyl–aryl coupling. The extent of carbometalation can be distinctly reduced through substitution of HOM for 1-hydroxyethyl. The strategy of polar tagging is

• -diiodobenzene a better procedure is presented together with the finding that 1,4-dialkyl-2,3-diiodobenzene, a constitutional isomer of 1,4-dialkyl-2,5-diiodobenzene, is one of the byproducts. Keywords: alkyne protecting group; carbometalation; C–C coupling; phenyleneethynylene; polar tagging; Introduction

• : (1) The type of MnO2 used for the removal of the HOM group, (2) carbometalation, a side reaction when using hydroxymethyl as an alkyne protecting group, (3) purity of 1,4-dihexyl-2,5-diiodobenzene, and (4) polar tags in the side chains of building blocks to reduce the number of steps in oligomer