Optically Active Amines. 41.¹ Application of the Benzene Chirality Rule to Chiral Ring-Substituted Benzylcarbinamines and Benzylcarbinamine Salts

Abstract

The sign of the 1 L b Cotton effects (CEs) of the benzene chromophore from about 240 to 270 nm in the circular dichroism (CD) of enantiomers of ring-substituted chiral benzylcarbinamines and benzylcarbinamine salts are correlated with their absolute configurations using the benzene sector rule and a consideration of the equilibrium between their two conformers of lowest energy and of oppositely signed rotatory power. These CEs are the result of vibronic borrowing from allowed transitions of the benzene chromophore at shorter wavelength, but an induced rotatory contribution, the sign of which may be predicted using the benzene chirality rule, is small compared to the vibronic contribution and need not be considered when predicting the sign of the 1 L b CEs.

Chemoenzymatic One‐Pot Synthesis of Enantiopure L‐Arylalanines from Arylaldehydes

“…All analytical and physical data for the isolated and purified -amino acids are in good agreement with the literature data. [14,20,21] Aldehydes 1a-d, (triphenyl-λ 5 -phosphanylidene)ethyl acetate, porcine liver esterase (PLE) and ion-exchange resin (Dowex 50X8) were products of Aldrich, Fluka or Sigma.…”

Synthesis and Explosion Hazards of 4-Azido-l-phenylalanine

“…For example, previously reported optical rotation values for 1 are −20°, −10.6°, −9.1°, −6.2°, and +20°. 3a,7,36 We note that variation in both sign and magnitude is reported, despite each value being measured apparently from the same stereoisomer. The literature characterization data of 4 is similarly poor.…”

Derivatization, complexation, and absolute configurational assignment of chiral primary amines: Application of exciton‐coupled circular dichroism

“…The appropriate shape is present, and while the amplitudes are somewhat diminished compared to similar complexes, 36,37 they are still strong compared to the amines from which they are derived. 40,41 Ideally, the wavelength of the null in the bisignate CD spectrum should correspond to the max of a peak in the UV-vis spectrum, centered between the two Cotton effects with opposite signs. , 238 nm shoulder, 1 B b ).…”