Scope of the allylation reaction with [RuCp(PP)]⁺ catalysts: changing the nucleophile or allylic alcohol

Abstract

The scope of the dehydrative allylation reaction using allyl alcohol as allyl donor with [RuCp(PP)] + complexes as catalysts is explored. Aliphatic alcohols are successfully allylated with allyl alcohol or diallyl ether, obtaining high selectivity for the alkyl allyl ether. The reactivity of aliphatic alcohols is in the order of primary > secondary >> tertiary. The tertiary alcohol 1-adamantanol reacts extremely slowly in the absence of strong acid, but when HOTs is added, reasonable yields of 1-adamantyl allyl ether are obtained. The alkyl allyl ether is found to be the thermodynamically favored product over diallyl ether. Apart from alcohols, thiols and indole are also efficiently allylated, while aniline acts as a catalyst inhibitor. Allylation reactions with various substituted allylic alcohols give products with retention of the substitution pattern. It is proposed that a Ru(IV) σ -allyl species plays a key role in the mechanism of these allylation reactions.

Transition metal catalyzed nucleophilic allylic substitution: activation of allylic alcohols via π-allylic species

“…Thus, aliphatic alcohols (ethanol, butanol, octanol, 2,3,4,6-tetra-O-benzyl-D-glucose), indole, hexanethiol, and thiophenol were successfully allylated by allyl alcohol. 56 This catalytic system however failed for allylation of an aromatic amine such as aniline, and diethyl malonate. When two monophosphine ligands were used instead of a bidentate ligand as in [RuCp(PPh 3 ) 2 ]OTs 2, the isomerisation of allyl alcohol into propanal was the main reaction even in the presence of a phenol as nucleophile.…”

Reactive Extrusion Synthesis of Biobased Isocyanate-Free Hydrophobically Modified Ethoxylated Urethanes with Pendant Hydrophobic Groups

“…The green approach to the synthesis of IFHEURs was enhanced by the incorporation of a CO 2 molecule to produce each cyclic carbonate group of BCC, which is subsequently built into the urethane bonds. For future developments, the functionalization of PEG with glycidyl groups, needed for the synthesis of BCC, can also be achieved starting from biobased glycerol, subsequently converted to allyl alcohol, allyl-terminated PEG, and finally to the PEG diglycidyl ether. − Moreover, we carried out the hydrophobic modification toward IFHEURs by solvent-free REX using fatty diamine based on fully renewable carbon sourcesPRIAMINE 1075, which contains two pendant aliphatic tails, as shown in Scheme . The chain extension of PHU prepolymers in varied formulations with the diamine formed strongly hydrophobic centers, distributed between the hydrophilic segments of the IFHEURs.…”

Straightforward synthesis of ferrocenyl allylic thioethers

“…In the last decades, many efforts have been devoted to the synthesis of allyl thioethers, 1,2,3,4,5,6,7,8,9,10,11,12,13 because these compounds may have interesting properties in many areas such as biochemistry and medicinal chemistry, 14,15 materials science 16 or synthetic organic chemistry as synthetic intermediates. 17,18,19,20,21,22 Despite the huge interest for ferrocene derivatives in many areas such as catalysis, 23,24,25,26,27,28,29,30 supramolecular chemistry 31,32 and sensing, and medicinal chemistry, 33,34 no ferrocene-containing allyl thioethers have been described so far to the best of our knowledge.…”

“…5] + and branched[6] + , are, in fact, never present in the reaction mixture, ruling out the equilibration pathways presented in Scheme 2. This leads us to propose that the reaction regioselectivity (Table1, entries 1, 5 and 7) corresponds to the regioselectivity of the nucleophile addition to the intermediate carbocation, without further equilibration.…”