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An Attractive Route to Olefin Metathesis Catalysts: Facile Synthesis of a Ruthenium Alkylidene Complex Containing Labile Phosphane Donors
Author(s) -
Amoroso Dino,
Snelgrove Jennifer L.,
Conrad Jay C.,
Drouin Samantha D.,
Yap Glenn P. A.,
Fogg Deryn E.
Publication year - 2002
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/1615-4169(200208)344:6/7<757::aid-adsc757>3.0.co;2-x
Subject(s) - chemistry , carbene , ruthenium , carbyne , metathesis , olefin metathesis , catalysis , medicinal chemistry , olefin fiber , salt metathesis reaction , stereochemistry , benzene , organic chemistry , polymer , polymerization
Reaction of RuHCl(PPh 3 ) 3 4 with 3‐chloro‐3‐methyl‐1‐butyne effects transformation into RuCl 2 (PPh 3 ) 2 (CHCHCMe 2 ) 1c . Starting 4 is available commercially, or via quantitative reaction of RuCl 2 (PPh 3 ) 3 with one equivalent of alkali phenoxides or isopropoxides in refluxing benzene‐2‐propanol. Phosphane exchange between 1c and PCy 3 or 1,3‐(CH 2 PCy 2 ) 2 C 6 H 4 is rapid at RT, affording RuCl 2 (PCy 3 ) 2 (CHCHCMe 2 ) 1b or the novel alkylidene complex RuCl 2 [1,3‐(CH 2 PCy 2 ) 2 C 6 H 4 ](CHCHCMe 2 ) 7 . Much slower exchange occurred on use of RuCl 2 (PCy 3 ) 2 (CHPh) ( 1a ) as precursor. Complex 1c is stable indefinitely (months) in the solid state at RT under N 2 , but dimerizes slowly in solution to give RuCl(PPh 3 ) 2 (μ‐Cl) 3 Ru(PPh 3 ) 2 (CHCHCMe 2 ) 6a . 2,7‐Dimethyl‐octa‐2,4,6‐triene, the formal product of carbene coupling, is observed by 1 H NMR. Dimerization does not compete with phosphane exchange. A side‐product arising from use of excess 3‐chloro‐3‐methyl‐1‐butyne in the synthesis of 1c was identified as Ru(IV) carbyne complex RuCl 3 (PPh 3 ) 2 (≡CCHCMe 2 ) 5 , the structure of which was confirmed by X‐ray crystallography.