Origin of chiral induction in radical reactions with the diastereoisomers (5R)- and (5S)-5-l-menthyloxyfuran-2[5H]-one.
Acetalization of 5-hydroxyfuran-2[5H]-one with l-menthol yields (5R)- (1) and (5S)-5-l-menthyloxyfuran-2[5H]-one (2) in equal amounts. The diastereomer 1 crystallizes preferentially. For the first time, the isolation of pure diastereoisomer 2 is reported. Different diastereoselectivities were observed in the radical tandem reaction of 1 and 2 with N,N-dimethylaniline. The privileged conformations in solution of the substrates and the products of the radical reaction were then determined, and X-ray crystal structure analyses were carried out on the reaction products. The different stereoselectivities in both cases are explained by different orientations of the menthyloxy substituent.
Marinković
Sinisa
S
Laboratoire des Réactions Sélectives et Applications, UMR (6519) CNRS et Université de Reims Champagne-Ardenne, UFR Sciences, B.P. 1039, F-51687 Reims, Cedex 2, France.
Brulé
Cédric
C
Hoffmann
Norbert
N
Prost
Elise
E
Nuzillard
Jean-Marc
JM
Bulach
Véronique
V