A Synthetic Route to Highly Substituted 1,2,3,4-Tetrahydroisoquinolines via Yb(OTf)3-Catalyzed Diastereoselective Ring Opening of Bridged Oxazolidines: Asymmetric Synthesis of 2-Azapodophyllotoxin
作者:Ajay Kumar Srivastava、Minseob Koh、Seung Bum Park
DOI:10.1002/chem.201002938
日期:2011.4.18
aldehydes and transformed into fully functionalized THIQs via diastereoselective ring opening with various nucleophiles in the presence of Yb(OTf)3. This methodology furnished four out of eight possible diastereomers of 1,2,3,4‐tetrasubstituted THIQs despite the electronic nature of substituents on the aryl rings. Finally, the enantioselective synthesis of 2‐azapodophyllotoxin was achieved with an overall
我们在此报告了一种从Garner醛向高度官能化的对映纯1,2,3,4-四氢异喹啉(THIQs)的稳健而有效的合成途径。我们通过1,2-和1,3- / 1,4-不对称诱导利用Garner醛的固有手性来迭代获得1,2,3,4-四取代的THIQ,这些化合物使用刚性且可分离的桥接恶唑烷,无需任何外部手性来源。从L-和D-加纳尔醛中高效合成了桥接的恶唑啉二烯的所有可能的立体异构体,并在Yb(OTf)3存在的情况下,通过与各种亲核试剂的非对映选择性开环将其转化为功能完全的THIQ。尽管在芳基环上具有取代基的电子性质,该方法仍提供了1,2,3,4-四取代的THIQ的八种可能的非对映异构体中的四种。最终,使用该合成路线从D- Garner醛中获得了2-氮杂鬼臼毒素的对映选择性合成,总收率为35.4%(八步)。