Density functional theory (DFT) calculations of sodium D line specific rotation and of vibrational circular dichroism (VCD) have been used to assign the absolute configuration of a recently prepared (1S,4R)-norcamphor-derived furyl hydroperoxide, (+)-3, introduced as a stereoselective oxidant. Both approaches give the same absolute configuration to the newly generated stereogenic carbon at position 2, i.e., (1S,2S,4R)-(+)-3, thus providing a 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 possible diastereoisomers can be observed, which allows the structural identification of the synthesized Compound. This is clearly shown here for the first time.
Absolute Configuration Assignment of Norcamphor-Derived Furyl Hydroperoxide Using Density Functional Theory Calculations of Optical Rotation and Vibrational Circular Dichroism
LATTANZI, Alessandra;SCETTRI, Arrigo;ZANASI, Riccardo;
2010-01-01
Abstract
Density functional theory (DFT) calculations of sodium D line specific rotation and of vibrational circular dichroism (VCD) have been used to assign the absolute configuration of a recently prepared (1S,4R)-norcamphor-derived furyl hydroperoxide, (+)-3, introduced as a stereoselective oxidant. Both approaches give the same absolute configuration to the newly generated stereogenic carbon at position 2, i.e., (1S,2S,4R)-(+)-3, thus providing a 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 possible diastereoisomers can be observed, which allows the structural identification of the synthesized Compound. This is clearly shown here for the first time.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
