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

Article abstract of DOI:10.3987/COM-12-12480

The reductive degradation of taxine NA-1 (2'-hydroxytaxine II) with n-Bu₄NBH₄ gave taxinine A and (-)-3-dimethylamino-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 Sharpless 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, 3S) 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).