DETERMINATION OF THE STEREOCHEMISTRY OF C-2 ' AND C-3 ' POSITIONS OF TAXINE NA-1 (2 '-HYDROXYTAXINE II) BY THE ASYMMETRIC SYNTHESIS OF THE REDUCTIVE DEGRADATION PRODUCT OF ITS SIDE CHAIN MOIETY

• Published in: Heterocycles Vol. 85; no. 7; pp. 1697 - 1711
• Main Authors: Tang, Wanxia, Minato, Hiroshi, Ando, Mariko, Ando, Masayoshi
• Format: Journal Article
• Language: English
• Published: OXFORD Elsevier 01.07.2012
• Subjects: Chemistry; Chemistry, Organic; Physical Sciences; Science & Technology; (2R,3S)-3-and (2S,3R)-3-Dimethylamino-3-phenylpropane-1,2-diols; Sharpless Asymmetric Epoxidation; TAXOL; Taxine NA-1; TAXUS-CUSPIDATA
• ISSN: 0385-5414
• DOI: 10.3987/COM-12-12480

The reductive degradation of taxine NA-1 (2'-hydroxytaxine II) with n-Bu4NBH4 gave taxinine A and (-)-3-dimethylarnino-3-phenylpropane-1,2-diol (1) in addition to 11,12-dihydrotaxinine A. The relative stereochemistry of (-)-1 was identical with syn-3-dimethylamino-3-phenylpropane-1,2-diol, (+/-)-1b, which was synthesized from cis-2,3-epoxy-3-phenylpropan-1-ol, (+/-)-7. The absolute configuration of (-)-1 was certified by comparison of the specific optical rotation and the spectroscopic data of (-)-1 with those of (+)-1b and (-)-1b, which were enantioselectively synthesized by Sharp less asymmetric epoxidation reaction of cis-cinnamyl alcohol (6), respectively. As the result, the relative and absolute configuration of (-)-1 was same with that of (-)-1b possessing (2R, 35) configuration. Thus, the absolute configuration of the side chain of taxine NA-1 (2'-hydroxytaxine II) at C-2' and C-3' positions was determined to be (2'R, 3'S).