Direct preparation of benzylic manganese reagents from benzyl halides, sulfonates, and phosphates and their reactions: applications in organic synthesis
作者:YoungSung Suh、Jun-sik Lee、Seoung-Hoi Kim、Reuben D Rieke
DOI:10.1016/s0022-328x(03)00500-x
日期:2003.11
The use of highly active manganese (Mn)*, prepared by the Rieke method, was investigated for the direct preparation of benzylic manganese reagents. The oxidative addition of the highly active manganese to benzylic halides was easily completed under mild conditions. Moreover, benzylic manganese sulfonates and phosphates were prepared by direct oxidative addition of Mn* to the carbon–oxygen bonds of
Palladium/Xiao‐Phos‐Catalyzed Kinetic Resolution of
<i>sec</i>
‐Phosphine Oxides by
<i>P</i>
‐Benzylation
作者:Qiang Dai、Lu Liu、Junliang Zhang
DOI:10.1002/anie.202111957
日期:2021.12.20
rac-secondary phosphine oxides via the enantioselective P-benzylation process catalyzed by the palladium/Xiao-Phos was designed. Both, tert- and sec-phosphine oxides were delivered in good yield and excellent enantiopurity (selectivity factor up to 226.1). The synthetic utilities are further demonstrated by the facile preparation of several P-chiral compounds, precursors of bidentate ligands, and transition
Synthesis of Functionalized Diarylmethanes via a Copper-Catalyzed Cross-Coupling of Arylmagnesium Reagents with Benzylic Phosphates
作者:Christiane C. Kofink、Paul Knochel
DOI:10.1021/ol0616790
日期:2006.8.1
A combination of copper chloride, triethyl phosphite, and tetrabutylammonium iodide is a very efficient catalytic system for the synthesis of polyfunctionalized diarylmethanes, using the cross-coupling reaction of arylmagnesium halides with benzylic phosphates. The antibiotic Trimethoprim has been prepared using this Cu(I)-catalyzed cross-coupling in 52% overall yield (four steps).
Al(OTf)3 exhibits superior catalyst performance in the Friedel–Crafts‐type benzylation using benzylicphosphate as an electrophile. The reaction can be conducted even with 0.2 mol‐% of the catalyst. Twenty‐one different diarylmethanes are formed. The chemoselective property of the catalyst toward the phosphate group over acetate and bromide is noteworthy.
Palladium-Catalyzed Asymmetric Benzylation of Azlactones
作者:Barry M. Trost、Lara C. Czabaniuk
DOI:10.1002/chem.201302390
日期:2013.11.4
Asymmetric benzylation of prochiral azlactone nucleophiles enables the catalytic introduction of a benzyl group towards the synthesis of α,α‐disubstituted amino acids. Herein, we report an enantioselective palladium‐catalyzed process using chiral bis(diphenylphosphinobenzoyl)diamine (dppba) ligands. Naphthalene‐ and heterocycle‐based methyl carbonates react with a number of azlactones derived from