ketone 15. The en/zu face selectivity of 15 in sodium borohydride reduction was enhanced to 32/68 in β-CD solution. Both 1,3-dipolar addition and dichlorocarbene addition reactions on 4-ethyleneketal-2-methyleneadamantane 13 underwent again predominant en-face attack to give products in an E/Z ratio of >99:1 and 92:8, respectively. The exceptional high zu-face selectivity on the dichlorocarbene addition