An industrially viable catalyst system for palladium-catalyzed telomerizations of 1,3-butadiene with alcohols.
The telomerization reaction of 1,3-butadiene with alcohols to give alkyl octadienyl ethers in the presence of palladium-carbene catalysts has been studied in detail. Unprecedented catalyst efficiency with turnover numbers (TON) up to 1,500,000 and turnover frequencies (TOF) up to 100,000 h(-1) have been obtained after optimization for the reaction of methanol in the presence of an excess of in situ generated carbene ligands. High yields (75-97 %) and catalyst productivities (TON 15,000-100,000) are observed for other aliphatic alcohols and phenols. For comparison five carbene-palladium(0) complexes have been synthesized and characterized by X-ray crystallography. Both electronic and steric effects on the stability and reactivity of the catalysts have been discussed on the basis of density functional theory calculations.
Leibniz-Institut für Organische Katalyse an der Universität Rostock e.V., Buchbinderstrasse 5-6, 18055 Rostock, Germany.
Ralf
R
Jackstell
Surendra
S
Harkal
Haijun
H
Jiao
Anke
A
Spannenberg
Cornelia
C
Borgmann
Dirk
D
Röttger
Franz
F
Nierlich
Mark
M
Elliot
Stuart
S
Niven
Kingsley
K
Cavell
Oscar
O
Navarro
Mihai S
MS
Viciu
Steven P
SP
Nolan
Matthias
M
Beller
D000438:Alcohols / Q000138:chemical synthesis / Q000737:chemistry*; D002070:Butadienes / Q000737:chemistry*; D002384:Catalysis; D018360:Crystallography, X-Ray; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010165:Palladium / Q000737:chemistry*; D013237:Stereoisomerism; D013997:Time Factors
D000438:Alcohols; D002070:Butadienes; D008024:Ligands; D009942:Organometallic Compounds; D010165:Palladium; C031763:1,3-butadiene