Tandem isomerization/telomerization of long chain dienes

Abstract

The first example of a tandem reaction involving double-bond migration in combination with telomerization is reported. Homogeneous and heterogeneous Ru catalysts were employed as isomerization catalysts, and telomerization was realized using a homogeneous Pd(0) precursor complex with a N-heterocyclic carbene (IMes) ligand. Overall conversions approaching 60% were achieved with the best selectivity to telomerization products of 91% attained at 11% conversion. Conversion was markedly higher in the presence of longer-chain alcohol (1-butanol) as the nucleophile (telogen).

The Telomerization of 1,3‐Dienes – A Reaction Grows Up

“…The combination of an isomerization of 1,4‐pentadiene to 1,3‐pentadiene with subsequent telomerization was developed using two different catalysts, making this an orthogonal tandem catalyzed reaction. Once again, the Pd/IMes catalytic system was used for an efficient telomerization and, in this case, heterogeneous ruthenium and palladium catalysts were used for the isomerization …”

Selective telomerisation of isoprene with methanol by a heterogeneous palladium resin catalyst

“…The overall TON (Table 2) from the catalyst recycle reactions is in the same order of magnitude as those obtained using an equivalent homogeneous catalyst. 29 The chemoselectivity and regioselectivity across each run remain largely unchanged, suggesting that the same active palladium species bonded to (dvds) and triphenylphosphine ligands is responsible for the activity across all runs. The loss of (dvds) ligand clearly deactivates the catalysts instead of simply modifying its reactivity.…”

“…However, the conversion decreased at a higher temperature, probably due to decomposition of the Pd species immobilised on the resin as we have recently observed in the equivalent homogeneous system. 29 The main telomerisation product obtained is the tail-to-tail isomer, which is the less favoured product in homogenous reactions, whether using a carbene IJPdIJIMes)IJdvds)) or triphenylphosphine as palladium ligand. Interestingly, higher temperatures, >70 °C, favoured the formation of an even greater proportion of tail-to-tail telomerisation isomer although conversion is compromised due to decomposition as previously mentioned.…”

“…It was also shown that longer-chain conjugated dienes could be telomerised 28 and internal longchain dienes could be converted in tandem isomerisationtelomerisation reactions. 29 Recent advances in catalyst development, especially the introduction of highly active carbene catalysts with the means of controlling the selectivity between dimerisation and telomerisation products, see e.g., 7,30 should promote a variety of novel applications.…”

Terpene‐Derived Highly Branched C30‐Amines via Palladium‐Catalysed Telomerisation of β‐Farnesene

“…Lately, NHC ( N ‐heterocyclic carbene) ligands were used, showing higher activity, even for sterically hindered nucleophiles . Aside from 1,3‐butadiene, other 1,3‐dienes have been converted, especially isoprene, but also piperylene, 1,3‐hexadiene, and β ‐myrcene (Figure ) …”