A convenient short cut from aromatic iodides to alkynylstannanes and their use for the straightforward preparation of polyacetylene and polymetallaacetylene polymers

摘要

The palladium-catalyzed cross-coupling reaction (Stille coupling) of aromatic iodides Ar-I and tributyl(ethynyl)tin Bu_3SnC ident to CH form the aromatic acetylides Ar-C ident to CH and the side product tributyltin iodide Bu_3SnI in equimolar amount. In situ addition of lithium diisopropylamide (LDA) to this crude mixture directly affords the tributyl(ethynyl)tin aromatics Ar-C ident to CH-SnBu_3 in high yield. In the case of the bis(iodoaromatic) I-Ar-I (Ar = phenyl, thiophene), this straightforward transformation affords the corresponding bis[tributyl(ethynyl)tin]derivative Bu_3Sn-C ident to C-Ar-C ident to C-SnBu_3. In the presence of Pd this latter species can be directly reacted with a second bis(iodoaromatic) or a bis(metaliodide) unit to form acetylenic and metallaacetylenic polymers with tailored monomer units inserted in a stereoregular polymer chain.