Studies Directed toward the Total Synthesis of Azaspiracid: Stereoselective Construction of C<sub>1</sub>−C<sub>12</sub>, C<sub>13</sub>−C<sub>19</sub>, and C<sub>21</sub>−C<sub>25</sub> Fragments
作者:Rich G. Carter、David J. Weldon
DOI:10.1021/ol006674w
日期:2000.11.1
[reaction: see text] The efficient entry to the C(1)-C(12), C(13)-C(19), and C(21)-C(25) fragments of azaspiracid is outlined. The C(1)-C(12) portion is constructed using a key asymmetric allenyl borane addition to the corresponding alpha,beta-unsaturated aldehyde. The synthesis of the C(13)-C(19) portion utilizes an Evans asymmetric alkylation followed by Sharpless asymmetric dihydroxylation. In addition
[反应:见正文]概述了氮杂杂螺酸的C(1)-C(12),C(13)-C(19)和C(21)-C(25)片段的有效入口。C(1)-C(12)部分是使用键不对称的烯基硼烷加成至相应的α,β-不饱和醛而制成的。C(13)-C(19)部分的合成利用Evans不对称烷基化,然后进行Sharpless不对称二羟基化。另外,详细描述了在Sharpless二羟基化过程中相邻手性恶唑烷酮错配效应的新颖解决方案。