31233-60-0Relevant articles and documents
Chemoselective Benzylation of Aldehydes Using Lewis Base Activated Boronate Nucleophiles
Hollerbach, Michael R.,Barker, Timothy J.
, p. 1425 - 1427 (2018/05/24)
A benzylation of aldehydes using primary and secondary benzylboronic acid pinacol esters is reported. Activation of the boronic ester with s-butyllithium rendered it nucleophilic toward aldehydes. The activated nucleophile chemoselectively transfers the benzyl group over the sec-butyl group, providing excellent yields of the benzylated products. 11B NMR experiments were performed to study the mechanism of this transformation.
A practical method to stereospecifically synthesize trans-stilbene derivatives
Jian, Yujuan,Sun, Gaojun,Li, Jiaming,Su, Dan,Li, Chuanrun,Zhong, Guochen
, p. 1423 - 1428 (2011/10/31)
A practical method to stereospecifically synthesize trans-stilbenes was developed via the one-pot benzylation-dehydration reaction of aromatic aldehydes with benzyltrimethylsilane (BTMS), which was driven by tetrabutylammonium fluoride (TBAF) in THF. At the same time a plausible description of the whole process was proposed and the effects of substituted groups on the reaction were investigated. Also this method was employed to synthesize three precursors of natural products with excellent yields, which demonstrated that this method is much efficient and practical in the synthesis of some natural products. A practical method to stereospecifically synthesize trans-stilbenes was developed via the one-pot benzylation-dehydration reaction of aromatic aldehydes with benzyltrimethylsilane, which was driven by tetrabutylammonium fluoride in THF. A plausible description of the whole process was proposed and the effects of substituted groups on the reaction were investigated. This method was employed to synthesize three precursors of natural products with excellent yields. Copyright
Preparation of polyfunctional arylmagnesium, arylzinc, and benzylic zinc reagents by using magnesium in the presence of LiCl
Piller, Fabian M.,Metzger, Albrecht,Schade, Matthias A.,Haag, Benjamin A.,Gavryushin, Andrei,Knochel, Paul
experimental part, p. 7192 - 7202 (2010/03/05)
The presence of LiCl considerably facilitates the insertion of magnesium into various aromatic and heterocyclic bromides. Several functional groups, such as -OBoc, -OTs, -Cl, -F, -CF3, -OMe, -NMe2, and -N 2NR2, are well tolerated. The presence of a cyano group leads in some cases to competitive reduction of the organic halide to the corresponding ArH compound. The presence of sensitive groups such as methyl or ethyl ester is tolerated upon in situ trapping of the intermediate magnesium reagent with ZnCl2. This method can also be applied to the preparation of functionalized benzylic zinc reagents from benzylic chlorides. In the case of di- or tribromoaryl derivatives, directing groups such as -OPiv, -OTs, -N2NR2, or -OAc orient the zinc insertion (Zn/LiCl) to the ortho-position, while the reaction with Mg/LiCl or Mg/LiCl/ZnCl 2 leads to regioselective insertion into the para-carbon-bromine bond. Large-scale experiments (20-100 mmol) for all of the metalation procedures are described.
Polyfunctional benzylic zinc chlorides by the direct insertion of magnesium into benzylic chlorides in the presence of LiCl and ZnCl2
Metzger, Albrecht,Piller, Fabian M.,Knochel, Paul
supporting information; experimental part, p. 5824 - 5826 (2009/04/13)
Benzylic zinc chlorides bearing various functional groups are smoothly prepared by the direct insertion of magnesium into benzylic chlorides in the presence of LiCl and ZnCl2. The Royal Society of Chemistry.
Regioselectivity of the rhodium-catalyzed hydroboration of vinyl arenes: Electronic twists and mechanistic shifts
Edwards, David R.,Hleba, Yonek B.,Lata, Christopher J.,Calhoun, Larry A.,Crudden, Cathleen M.
, p. 7799 - 7802 (2008/09/18)
Any substituent does it: The hydroboration of vinyl arenes with pinacol borane (HBPin) and cationic rhodium complexes selectively placed the boron proximal to the aryl rather than phenyl ring, regardless of whether this ring bears electron-donating or electron-withdrawing substituents. In competition experiments between styrene and various vinyl arenes, preferential hydroboration also occured at the substituted arene (see scheme). Hammett plots indicate a break in the mechanism. (Chemical Equation Presented).
