A simple and efficient synthesis of 1,3,5-tris[2-(3,5-diethynylphenyl)ethynyl]benzene from 1,3,5-triethynylbenzene

A concise and convenient three-step process is reported for preparation of 1,3,5-tris2-(3,5-diethynylphenyl)ethynyl]benzene from 1,3,5-triethynylbenzene and 2-hydroxypropyl group-protected peripheral monomers via a Sonogashira coupling?Cdeprotection reaction sequence. This approach had several advantages, for example high yields, short reaction time, and simple separation procedure. In the key step a modified Sonogashira reaction was developed, under which conditions the coupling of 1,3,5-triethynylbenzene and substituted iodobenzenes proceeded rapidly, giving the desired products in good to excellent yields.