The First Allylation of Esters by an Allylsilane: One‐Pot Domino Synthesis of Triallylmethane Derivatives

Abstract

We report the first successful allylation of aromatic esters by allyltrimethylsilane. The reaction is mediated by 0.3-1.0 equiv. of titanium tetrachloride (TiCl 4 ) at room temperature and leads in a multistep, one-pot reaction to quaternary triallylmethane derivatives 5. The most efficient ester possessed two ortho-methoxy substituents on the phenol ring. Mo-lecular modelling revealed the ability of this compound to form a bidentate titanium complex, thus improving the steric accessibility of the ester carbonyl to nucleophilic attack.

Adventures in Synthetic Organic Chemistry. A Personal Account

“…Although there was no report of such a reaction with esters, it occurred to me that esters might provide directly, via a Lewis acid catalyzed, three‐step domino process, triallyl methanes, compounds of interest in the synthesis of dendrimers. However, when we tried the reaction of allyl trimethyl silane with esters in the presence of various Lewis acids, there was no reaction, until we used o ‐nitrophenyl esters or o ‐methoxyphenyl esters as substrates, and TiCl 4 as a catalyst In that case, triallylmethanes were obtained in good yield in one pot even at room temperature . Here again we showed by molecular modeling the importance of metal complexation.…”

2,4,9‐Triazaadamantanes with “Clickable” Groups: Synthesis, Structure and Applications as Tripodal Platforms

“…The NMR spectra are in accordance with the literature data. [41] ({[4-(Prop-2-en-1-yl)hepta-1,6-dien-4-yl]oxy}methyl)benzene (O-benzyl triallylmethanol 3e). Sodium hydride (1.6 g of 60 % suspension in mineral oil, 39 mmol) was washed with anhydrous THF (3 × 10 mL) under an argon atmosphere, and THF (5 mL) and DMPU (5 mL) were added.…”