New Chiral Phosphoramidite Complexes of Iron as Catalytic Precursors in the Oxidation of Activated Methylene Groups

Molecules

Pushkar Shejwalkar¹  Nigam P. Rath¹ 

[1]¹University of Missouri - St. Louis, Department of Chemistry and Biochemistry, One University Boulevard, St. Louis, MO 63121, USA[2] height:6px

[3]"> ²Department of Chemistry and Biochemistry and Center for Nanoscience, University of Missouri - St. Louis, One University Boulevard, St. Louis, MO 63121, USA

关键词: iron;    phosphoramidites;    X-ray;    chiral at metal;    benzylic oxidations;   

DOI  :  10.3390/molecules15042631

来源: mdpi

【 摘 要 】

New phosphoramidite complexes of iron were synthesized and structurally characterized. Reaction of the known chiral phosphoramidites (RO)₂PNR’₂ (R = binaphthyl, R’ = CH₃, 1a; R = binaphthyl, R’ = benzyl, 1b) with [FeBr(Cp)(CO)₂] afforded the title compounds [FeBr(Cp)(CO)(1a,b)] (4a,b) in 34 and 65 % isolated yields as mixtures of diastereomers, since both the metal and the ligand are stereogenic. Similarly, reaction of 1b with [Fe(Cp)I(CO)₂] in the presence of catalytic [Fe(Cp)(CO)₂]₂ afforded [Fe(Cp)I(CO)(1b)] (5b) in 81% yield as a mixture of diastereomers. The molecular structures of 4a, 4b and 5 were determined, revealing a pseudo octahedral coordination geometry about the iron center. The new metal complexes are catalytically active in the oxidation of benzylic methylene groups to the corresponding ketones, utilizing t-BuOOH as oxidant (2 mol% catalyst, 36 h, room temperature, 31−80% yield).

【 授权许可】

CC BY   
This is an open access article distributed under the Creative Commons Attribution License (CC BY) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.