Absolute configuration and optical rotatory dispersion of methyl alkyl sulfoxides

Structure of the tri-o-thymotide–ethyl methyl sulfoxide (2:1) clathrate. Crystallographic estimation of the enantioselectivity

“…The sign of the optical rotation is noted upon dissolution of a single crystal of TOT and after complete racemization of the host the residual optical activity of the excess guest enantiomer can be measured. In the present case the (R) configuration could be correlated with the (-) isomer of ethyl methyl sulfoxide, in agreement with previous configuration assignments accomplished by other methods (Axelrod, Bickart, Goldstein, Green, Kjaer & Mislow, 1968;Pirkle & Beare, 1968).…”

Vibrational Circular Dichroism and Absolute Configuration of Chiral Sulfoxides:tert-Butyl Methyl Sulfoxide

“…The work of Drabowicz et al [20] confirmed the AC deduced by Axelrod et al [6] and eliminated the possibility that this might be in error. The utility of our study thus lies principally in demonstrating both the reliability [a] n in cm À1 ; D in 10 À40 esu 2 cm 2 ; R in 10 À44 esu 2 cm 2 .…”

“…The first assignment of AC in 1 by Axelrod et al [6] relied on the knowledge of the AC of its synthetic precursor, O-menthyl methanesulfinate, together with the assumption that the Grignard reaction leading to 1 occurs with inversion of configuration, as had been established for other sulfoxides. [7] The use of VCD does not require the knowledge of the AC of synthetic precursors (or, alternatively, of synthetic derivatives) and of the stereochemistry of reactions used in synthesising (or derivatising) the chiral sulfoxide of interest.…”

“…The mid-IR VCD spectrum of 1 is analysed using the recently developed DFT/GIAO methodology for the prediction of vibrational rotational strengths. [1±5] Optically active 1 was first synthesised by Axelrod et al [6] via Grignard reaction from O-menthyl-methanesulfinate. The known reaction stereochemistry (inversion) [7] led to the absolute configuration (AC): R(À)/S().…”

An Unprecedented Blue Chromophore Found in Nature using a “Chemistry First” and Molecular Networking Approach: Discovery of Dactylocyanines A–H

“…The absolute configuration of the sulfur atom of 9 and 10 , (methyl alkyl sulfoxide), was assigned, by application of the empirical Mislow rule, as R , because of the negative sign of the Cotton effect observed at 215 nm in the ECD spectrum of both compounds (see section S4 in the Supporting Information) …”