16282-15-8Relevant articles and documents
Regio- And Stereoselective (S N2) N -, O -, C - And S -Alkylation Using Trialkyl Phosphates
Banerjee, Amit,Hattori, Tomohiro,Yamamoto, Hisashi
, (2021/06/16)
Bimolecular nucleophilic substitution (S N 2) is one of the most well-known fundamental reactions in organic chemistry to generate new molecules from two molecules. In principle, a nucleophile attacks from the back side of an alkylating agent having a suitable leaving group, most commonly a halide. However, alkyl halides are expensive, very harmful, toxic and not so stable, which makes them problematic for laboratory use. In contrast, trialkyl phosphates are inexpensive, readily accessible and stable at room temperature, under air, and are easy to handle, but rarely used as alkylating agents in organic synthesis. Here, we describe a mild, straightforward and powerful method for nucleophilic alkylation of various N -, O -, C - and S -nucleophiles using readily available trialkyl phosphates. The reaction proceeds smoothly in excellent yield, and quantitative yield in many cases, and covers a wide range of substrates. Further, the rare stereoselective transfer of secondary alkyl groups has been achieved with inversion of configuration of chiral centers (up to 98% ee).
Reactivity and Selectivity in the Oxidation of Styrene Derivatives. IV. Studies on the Oxidation of Substituted β,β-Dimethylstyrenes
Suprun
, p. 247 - 255 (2007/10/03)
The liquid phase oxidation of substituted (p-MeO-, p-Cl-, m-CF3-) 2-aryl-3-methyl-but-2-enes, of 1,1-diphenyl-2-methyl-propene, of 1-ethoxy-2-methyl-1-phenyl-propene and of 9-isopropylidene-fluorene with pure oxygen was investigated in chlorobenzene solution and in presence of cumene and of cumene hydroperoxide in the temperature range 65-125°C. The product yields were determined gaschromatographically. The differences of the activation energies of epoxide formation and the parallel reactions were calculated. They amount to 19-48 kJ/mol. The epoxide selectivity increases with increasing temperature and increasing concentration of olefin. The relative chain propagation constants (kpC=C) were determined by competitive oxidation with cumene. The kpC=C values of substituted β,β-dimethylstyrenes can be correlated by a LFE-relationship with the ionisation energies of the olefins.