英语翻译Synthesis and Structure of Trigonal and Tetragonal Conne

英语翻译
Synthesis and Structure of Trigonal and Tetragonal Connectors
for a “Tinkertoy” Construction Set
Peter F.H.Schwab,Bruce C.Noll,and Josef Michl*
Department of Chemistry and Biochemistry,University of Colorado,Boulder,Colorado 80309-0215
michl@eefus.colorado.edu
Received February 15,2002
We describe a convergent synthesis of eight 1,3,5- and 1,2,4,5-substituted benzene derivatives with
long rigid arms containing 4-pyridyl,2,2¢-bipyridyl,and 2,2¢-bipyrimidyl termini,meant to be used
as trigonal or tetragonal connectors for the construction of large molecular structures.The synthesis
involved copper-free Pd-mediated coupling of terminal acetylenes to aryl halides.First,one of the
termini of 1,3-diethynylbicyclo[1.1.1]pentane was coupled with a brominated aza heterocycle,and
second,3 equiv of the resulting extended arm were coupled with 1,3,5-triiodobenzene or 4 with
1,2,4,5-tetraiodobenzene.An improved large-scale synthesis for 1,3-diethynylbicyclo[1.1.1]pentane
is described.The structures of two of the arms were determined by single-crystal X-ray analysis.
Several long molecular rods with 4-pyridyl termini were obtained as byproducts,and a singlecrystal
X-ray structure is reported for the shortest of these.