Enantioselective Vanadium-Catalyzed Oxidation of 1,3-Dithianes from Aldehydes and Ketones using β-Amino Alcohol Derived Schiff Base Ligands
作者:Yinuo Wu、Fei Mao、Fanchao Meng、Xingshu Li
DOI:10.1002/adsc.201000803
日期:2011.7
and ketones by β‐amino alcohol‐derived Schiffbase ligands with two stereogenic centers was investigated. Usingaqueoushydrogenperoxide as the oxidant and the Schiffbase 3b as a chiral ligand, a variety of 1,3‐dithianes derived from aldehydes were easily converted into the corresponding mono‐sulfoxides in good yields (81–88%) with excellent enantioselectivities (up to 99% ee). Additionally, 99% ee
The mass spectra of 20 1,3-dithianes were studied. The fragmentation patterns including the loss of 74 u and 107 u and clearage of the substituent at C-2 depended strongly on the nature of the substituents at that position. 2,2-Diphenyl-1,3-dithiane undergoes an atypical fragmentation in which two hydrogens migrate from the phenyl ring, with the formation of a fluorene skeleton.