Effects of Beta-cyclodextrins and It's Derivatives on the Face Selectivity of NaBH4 Reduction of 5-Substitutedadamantan-2-ones

• Main Authors: Gow-Wei Sun, 孫國維
• Other Authors: Wen-Sheng Chung
• Format: Others
• Language: zh-TW
• Published: 1995
• Online Access: http://ndltd.ncl.edu.tw/handle/00453234659991722845

碩士 === 國立交通大學 === 應用化學系 === 83 === The reduction of 5-substituted-adamantan-2-one (5-X-ADs) by NaBH4 is found to favor the syn-pi-face attack of nucleophile due to electronwithdrawing substituents. In the present of beta- cyclo- n(beta-CD),5-X-AD can form an inclusion complex with the hydrophibic cavity of CD.This leads to the protection of syn- pi- face of 5-X-AD and a reversed face selectivity was observed. Beside Cl and Br substituents, we also added bigger substituents as SnMe3 and different substituted phenyl groups. Our results show that, for small substituent (such as F), beta-CD has almost no effect on pi-face selectivity, however, for large substituent such as SnMe3, enhanced syn- attack was found. In this work, we also use seneral modified beta-CDs in combination with different 5-X-ADs to study their size and shape relationships for inclusion complexes and their effects on face selectivity. 2-Br and 2-Cl are found to undergo SN1 rection in the process of basic reduction (NaBH4 and 0.01 N NaOH);i.e. Br- and Cl- substituents arereplaced by -OH. All beta-CDs studied here can protect 2-Br and 2-Cl form SN1 reaction no matter whether they change the face-selectivity or not. H-NMR was used to prove the inclusion complex formation of 5-acryl-ADs with beta-CDs.