Alternative syntheses of versatile chiral intermediate for drimane sesquiterpenes and labdane diterpenes using (R,R)-cycloheptane-1,2-diol as a chiral auxiliary
作者:Hiroyuki Akita、Youhei Amano、Keisuke Kato、Masako Kinoshita
DOI:10.1016/j.tetasy.2003.12.040
日期:2004.2
The resolution of the enantiomers of (±)-β-keto ester 6 using (R,R)-cycloheptane-1,2-diol as a chiral auxiliary for acetal formation was carried out with the enantiomerically pure (8aR)- and (8aS)-decahydro-5,5,8a-trimethyl-2-oxo-naphthalene-1-methanols 7 and (8aR)- and (8aS)-decahydro-5,5,8a-trimethyl-2-oxo-naphthalene-1-carboxylates 6 being obtained. Both (10R)- and (10S)-15,16-epoxy-8(17),13(16)
使用(R,R)-环庚烷-1,2-二醇作为缩醛形成的手性助剂,拆分(±)-β-酮酸酯6的对映异构体是通过对映体纯的(8a R)-和( 8a S)-十氢-5,5,8a-三甲基-2-氧代萘-1-甲醇7和(8a R)-和(8a S)-十氢-5,5,8a-三甲基-2-氧代-得到萘-1-羧酸酯6。(10 R)-和(10 S)-15,16-环氧-8(17),13(16),14-labdatriene 4都是由(8a R)-和(8a S)-羟基酮((7)分别将自然(-)- 4的绝对构型明确地确定为(5 R,9 R,10 R)。另一方面,由(8a R)-和(8a S)-β-合成了(10 R)-和(10 S)-15,16-环氧-7,13(16),14-labdatriene 5。如方案1所示,分别确定酮酸酯6和天然(+)- 5的相对结构。