A renewable tertiary hydroperoxide has been efficiently synthesized in 83% overall yield starting from commercially available (+)-endo-2-norborneol. This oxygen donor, derived from (+)-norcamphor, when employed in Ti(O i-Pr)(4)-catalyzed sulfoxidations, proved to be considerably more reactive when compared to a previously reported camphor-derived hydroperoxide. Reduced steric hindrance of the new oxidant lowered the level of asymmetric induction achieved in the oxidation, but stereo-convergent kinetic resolution has been exploited to improve enantioselectivity. Excellent recovery (95%) of the tertiary alcohol at the end of the sulfoxidation provides a highly advantageous chiral resource saving protocol. (C) 2004 Elsevier Ltd. All rights reserved.
Absolute Configuration Assignment of Norcamphor-Derived Furyl Hydroperoxide Using Density Functional Theory Calculations of Optical Rotation and Vibrational Circular Dichroism
作者:Alessandra Lattanzi、Arrigo Scettri、Riccardo Zanasi、Frank J. Devlin、Philip J. Stephens
DOI:10.1021/jo902472b
日期:2010.4.2
confident assignment in a case made difficult by the large conformational flexibility and the small difference between the computed optical rotations of the two possible diastereoisomers. Although the computed IR absorption spectra of (1S,2S,4R)-3 and (1S,2R,4R)-3 are practically indistinguishable, a number of significant differences in the VCD spectra of these two nonmirror-image isomers can be observed