Asymmetric catalytic [4 + 1] annulations catalyzed by quinidine: enantioselective synthesis of multi-functionalized isoxazoline N-oxides
作者:Zhi-Wei Guo、Jian-Wu Xie、Ce Chen、Wei-Dong Zhu
DOI:10.1039/c2ob26165k
日期:——
multi-functionalized isoxazoline N-oxides with three stereogenic centers including adjacent quaternary and tertiary stereocenters has been developed. Notably, the unexpected product ethyl 2-((tert-butyldimethylsilyl)oxy)-2-(5,5-diacetyl-3-((methylsulfonyl)oxy)-4-phenylisoxazolidin-3-yl)acetate (8) bearing a quaternary stereocenter and two tertiary stereocenters was obtained from the undocumented 5,
具有高区域,化学,非对映和对映选择性的有机催化[4 +1]与Morita–Baylis–Hillman加合物的2-卤代-1,3-二羰基化合物的环化反应,可通过商业途径获得,成本低 奎尼丁用于制备具有三个立体生成中心,包括相邻的季和叔立体中心的合成独特的和医学上多功能的异恶唑啉N-氧化物。值得注意的是,意想不到的产品2-((叔丁基二甲基甲硅烷基)氧基)-2-(5,5-二乙酰基-3-((甲基磺酰基)氧基)-4-苯基异恶唑烷-3-基)乙酸乙酯(8)从未记录的5,5-二乙酰基-3-(2-乙氧基-1-羟基-2-氧代乙基)-4-苯基-4,5-二氢异恶唑2-氧化物中获得了具有一个四级立体中心和两个三级立体中心的化合物(4ba)。