3-[(3R,4S,5R)-5-[(R)-1,2-Bis-(tert-butyl-dimethyl-silanyloxy)-ethyl]-3,4-bis-(tert-butyl-dimethyl-silanyloxy)-dihydro-furan-(2Z)-ylidene]-propan-1-ol 在
camphor-10-sulfonic acid 作用下,
以100%的产率得到(2R,3S,4R)-2-[(R)-1,2-Bis-(tert-butyl-dimethyl-silanyloxy)-ethyl]-3,4-bis-(tert-butyl-dimethyl-silanyloxy)-1,6-dioxa-spiro[4.4]nonane