摘要 |
<p>The present invention relates to a process (Mukaiyama Aldol reaction) for thepreparation of compounds of formula (I) wherein R1 is C1-4 alkyl, C3-6 cycloalkyl-C1-4 alkyl or aryl-C1-4 alkyl; R2 is C1-4 alkyl, benzyl, substituted benzyl or allyl; R3 is C1-4 alkyl or allyl; R4 is C1-4 alkyl, allyl, benzyl or substituted benzyl; R4' is benzyl or substituted benzyl; or R1 and R4 together form a (CH2)3-group.</p> |