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Cross Coupling of Acetylenes with Olefins – Formation of η 3 ‐Butadienyl and η 2 ‐Butadiene Complexes via a Metallacyclobutane Intermediate
Author(s) -
Slugovc Christian,
Mereiter Kurt,
Schmid Roland,
Kirchner Karl
Publication year - 1999
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/(sici)1099-0682(199907)1999:7<1141::aid-ejic1141>3.0.co;2-4
Subject(s) - chemistry , deprotonation , electrophile , nucleophile , 1,3 butadiene , medicinal chemistry , coupling (piping) , stereochemistry , hydrogen , organic chemistry , catalysis , mechanical engineering , ion , engineering
Selective coupling of olefins and terminal acetylenes is shown to be effected in the coordination sphere of Ru II by the successive intermediacy of vinylidene and ruthenacyclobutane complexes. Subsequent deprotonation of one of the β‐hydrogen atoms of the latter by NaOEt yields η 3 ‐butadienyl complexes, while in the presence of Cl − rearrangement takes place to give neutral η 2 ‐butadiene complexes by a β‐hydrogen elimination/reductive elimination sequence. [Ru(tp)(COD)Cl] and [Ru(tp){η 3 ‐( P , C , C )‐Ph 2 PCH=CHC(Ph)=CH 2 }Cl] were the starting materials which were treated with HC≡CR (R = Ph, C 6 H 9 , ferrocenyl, CH 2 Ph, n Bu). The η 3 ‐butadienyl complexes are nucleophilic at the enynyl carbon atom reacting readily with the electrophiles H + and I 2 to give the corresponding η 2 ‐butadienyl complexes. X‐ray structures of representative products are given.