(2R,4S)-4-(R)-1,4-Dioxa-spiro[4.5]dec-2-yl-4-methoxy-2-methyl-butyryl chloride 、
(S)-1-(2-Benzyloxycarbonyl-acetyl)-piperidine-2-carboxylic acid benzyl ester 在
异丙基氯化镁 作用下,
生成 (S)-1-((Z)-(4R,6S)-2-Benzyloxycarbonyl-6-(R)-1,4-dioxa-spiro[4.5]dec-2-yl-3-hydroxy-6-methoxy-4-methyl-hex-2-enoyl)-piperidine-2-carboxylic acid benzyl ester