| 摘要 |
The present invention relates to processes for the preparation of compounds of formula IB wherein A1, A2, A3, A4, L, Y1, Y2, R1, R2, R3, R4 and R5 are as defined in the claims, comprising reacting a compound of formula (II) wherein Y1, Y2, L, A1, A2, R1, R2, R3, R4 and R5 are as defined for the compound of formula (I); with hydroxylamine in the presence of water, a base and a chiral phase transfer catalyst, which chiral phase transfer catalyst is a quinine derivative. The invention also relates to compounds of formula IB and enantiomerically enriched mixtures comprising compounds of formula IB. |
