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1,3‐Diethynylbicyclo[1.1.1]pentane, a Useful Molecular Building Block
Author(s) -
Kaleta Jiří,
Nečas Marek,
Mazal Ctibor
Publication year - 2012
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201200351
Subject(s) - chemistry , pentane , umpolung , sonogashira coupling , aryl , molecule , electrophile , block (permutation group theory) , lithium (medication) , combinatorial chemistry , stereochemistry , organic chemistry , alkyl , palladium , catalysis , nucleophile , medicine , geometry , mathematics , endocrinology
1,3‐Diethynylbicyclo[1.1.1]pentane (DEBCP) has been found to be a valuable molecular building block mostly for the synthesis of extended, rigid, rod‐like molecules. With its straightforward linear geometry, DEBCP can be used as a nonconjugated alternative to more frequently used π‐conjugated, rod‐like building blocks. Examples of reactions that introduce DEBCP into larger structures are (1) the reaction of DEBCP lithium acetylides with electrophiles such as TMSCl, CO 2 , and Ph 2 PCl, (2) Sonogashira–Hagihara cross‐coupling reactions with aryl or heteroaryl iodides or bromides, and (3) umpolung reactions that afford the corresponding dibromo and diiodo derivatives of DEBCP, which then successfully react with tert ‐ C ‐cuprates derived from p ‐ and m ‐dicarbadodecaboranes or bicyclopentanes. These umpolung reactions afforded a new class of molecular rods that combine carborane or bicyclo[1.1.1]pentane cages with ethynylene linkers. Many of the DEBCP derivatives were studied by single‐crystal X‐ray diffraction. They form well‐organized arrays of molecular rotors, the DEBCP units, and so can be considered as examples of artificial molecular‐size machines.