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Synthesis of fluorenylidene‐ and 9‐alkylidene‐3,6‐dimethyl‐4,5‐diazafluorene compounds from 2,2′‐biarene‐3,3′‐diyl bis(triflate) by a palladium‐catalyzed domino process
Author(s) -
König Burkhard,
Bubenitschek Peter,
Jones Peter G.
Publication year - 1994
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199519950127
Subject(s) - chemistry , trifluoromethanesulfonate , palladium , domino , moiety , intramolecular force , biphenyl , sonogashira coupling , catalysis , medicinal chemistry , organic chemistry
A convenient synthesis of the fluorenylidene and the 4,5‐diazafluorenylidene moiety is described. The palladium‐catalyzed coupling of 6,6′‐dimethyl‐2,2′‐bipyrdine‐3,3′‐diyl bis(triflate) ( 2 ) with phenylacetylene leads to the 4,5‐diazafluorenylidene compound 4 as the major reaction product by an intramolecular cyclization. Under the same conditions biphenyl‐2,2′‐diyl bis(triflate) ( 6 ) gives the threefold coupling product 7 . The connectivity of 4 and 7 is confirmed by crystal structure analysis.