(2R,3S,6S)-6-[(1S)-1-[(2R,3S,6S)-6-[(1S)-1-[(2R,3S,6S)-6-[(1S)-1-hydroxyethyl]-3-methyl-3,6-dihydro-2H-pyran-2-carbonyl]oxyethyl]-3-methyl-3,6-dihydro-2H-pyran-2-carbonyl]oxyethyl]-3-methyl-3,6-dihydro-2H-pyran-2-carboxylic acid 在
4-二甲氨基吡啶 、
compound 28 作用下,
以
甲苯 为溶剂,
以17%的产率得到(1R,4S,5S,8S,9R,12S,13S,16S,17R,20S,21S,24S,25R,28S,29S,32S,33R,36S,37S,40S,41R,44S,45S,48S)-4,8,12,16,20,24,28,32,36,40,44,48-dodecamethyl-3,11,19,27,35,43,49,50,51,52,53,54-dodecaoxaheptacyclo[43.3.1.15,9.113,17.121,25.129,33.137,41]tetrapentaconta-6,14,22,30,38,46-hexaene-2,10,18,26,34,42-hexone