TY - JOUR
T1 - Conformational arm-wrestling
T2 - Battles for stereochemical control in benzamides bearing matched and mismatched chiral 2- and 6-substituents
AU - Clayden, Jonathan
AU - Foricher, Yann J Y
AU - Helliwell, Madeleine
AU - Johnson, Paul
AU - Mitjans, David
AU - Vinader, Victoria
PY - 2006/2/7
Y1 - 2006/2/7
N2 - The orientation of a tertiary amide group adjacent to an aromatic ring may be governed by the stereochemistry of an adjacent chiral substituent. With a chiral substituent in both ortho positions, matched/mismatched pairs of isomers result. Evidence for matched stereochemistry is provided by the clean NMR spectra of single conformers, while mismatching gives poor or unexpected selectivities in the formation of chiral substituents, or mixtures of amide conformers. Attempts to use the match-mismatch effect to select for racemic pairs of enantiomeric substituents, and hence develop a "racemate- sequestering" reagent, are described, along with the use of "matching" to scavenge a single enantiomer of a diamine from material of incomplete enantiomeric purity.
AB - The orientation of a tertiary amide group adjacent to an aromatic ring may be governed by the stereochemistry of an adjacent chiral substituent. With a chiral substituent in both ortho positions, matched/mismatched pairs of isomers result. Evidence for matched stereochemistry is provided by the clean NMR spectra of single conformers, while mismatching gives poor or unexpected selectivities in the formation of chiral substituents, or mixtures of amide conformers. Attempts to use the match-mismatch effect to select for racemic pairs of enantiomeric substituents, and hence develop a "racemate- sequestering" reagent, are described, along with the use of "matching" to scavenge a single enantiomer of a diamine from material of incomplete enantiomeric purity.
UR - http://www.scopus.com/inward/record.url?scp=33645237111&partnerID=8YFLogxK
U2 - 10.1039/b514558a
DO - 10.1039/b514558a
M3 - Article (Academic Journal)
C2 - 16446801
AN - SCOPUS:33645237111
SN - 1477-0520
VL - 4
SP - 444
EP - 454
JO - Organic and Biomolecular Chemistry
JF - Organic and Biomolecular Chemistry
IS - 3
ER -