Acyl transfer of 8-acetoxy-2-oxazolinylquinoline assisted by hydrogen bonding formation
摘要:
A significant acceleration of acyl transfer has been achieved on 8-acetoxy-2-oxazolinylquinoline in the presence of benzylamine. Comparison of the aminolysis by the new acylating reagent with that of 8-acetoxyquinoline and 8-acetoxyquinoline-2-carbonitrile has been carried out. The results of these experiments suggest that the proximity of a supplementary basic atom to the ester group increases the participation effect of the basic site mainly by formation of a possible second hydrogen bond. The association constant of benzylamine into the basic cavity of 8-methoxy-2-oxazolinylquinoline (K-d = 80 M-1) has been measured by H-1 NMR titration experiments. (C) 2002 Elsevier Science Ltd. All rights reserved.
Palladium-catalyzed allylic alkylation using pyridino-oxazolines and quinolino-oxazolines as ligands—influence of steric factors
摘要:
Four new chiral pyridino- and quinolino-oxazolines were subjected to the palladium-catalyzed alkylation of 1,3-diphenyl-2-propenyl acetate. The enantioselectivity varied (82-88% ee) with the steric properties of the ligands. The results are discussed in connection with results previously obtained using analogous ligands. (C) 1998 Elsevier Science Ltd. All rights reserved.
Chiral pyridinooxazoline, quinolinooxazoline, bis(oxazolino)pyridine (pybox), and bisoxazoline (box) derivatives containing crown ether residues were prepared. Some of the ligands were assessed in substrate binding studies and in palladium catalyzed allylic alkylations. (C) 2003 Elsevier Ltd. All rights reserved.