Enantio- and diastereoselective synthesis of 4′-α-substituted carbocyclic nucleosides
摘要:
Enantio-and diastereoselective synthesis of 4-alpha-alkylcarbovir derivatives 5 were achieved based on Sakai's asymmetric alkylation of beta-keto esters. The key carbocyclic intermediate 14 was synthesized from 8 via an eleven-step sequence. Coupling of 14 with 2-amino-6-chloropurine followed by desilylation and subsequent hydrolysis gave the target compounds 5 in moderate yields. (C) 1998 Elsevier Science Ltd. All rights reserved.
Asymmetric, Protecting-Group-Free Total Synthesis of (+)-Caribenol A
作者:Jing-Chun Han、Lian-Zhu Liu、Chuang-Chuang Li、Zhen Yang
DOI:10.1002/asia.201300441
日期:2013.9
Caribenol Queen: A new asymmetric, protecting‐group‐freesynthesis of the marine tetracyclic diterpenoid (+)‐caribenol A (1) has been achieved. The enantioselective synthesis employed (S)‐methyl 1‐methyl‐2‐oxocyclopent‐3‐enecarboxylate as a chiral scaffold, and an intramolecular Diels–Alder (IMDA) reaction of substrate 3 afforded the [5.7.6] tricyclic core in compound 2.
Stereoselective synthesis of 4'-α-alkylcarbovir derivatives 4 was described based on asymmetric synthesis or a chemoenzymatic procedure. The asymmetric alkylation of chiral acetal 7 gave the alkylated enol ethers 9a-c possessing a chiral quaternary carbon. The key carbocyclic intermediates 14a-c were synthesized from 9a-c via eleven-steps. Coupling of 14a-c with 2-amino-6-chloropurine followed by desilylation and subsequent hydrolysis afforded the target compounds 4a-c in moderate yield. The optically active cyclopentene intermediates 5a-c and 6a-c were also prepared by enzymatic resolution of (±)-5a-c and (±)-6a-c, respectively.
作者:Lian-Zhu Liu、Jin-Chun Han、Guo-Zong Yue、Chuang-Chuang Li、Zhen Yang
DOI:10.1021/ja106585n
日期:2010.10.6
A unified strategy toward the asymmetric total synthesis of carbenol A is reported, featuring intramolecular Diels-Alder (IMDA) and biomimetic oxidation reactions as key steps.
Asymmetric Total Synthesis of Caribenol A via an Intramolecular Diels–Alder Reaction
作者:Jing-Chun Han、Lian-Zhu Liu、Yuan-Yuan Chang、Guo-Zong Yue、Jie Guo、Li-Yan Zhou、Chuang-Chuang Li、Zhen Yang
DOI:10.1021/jo4006156
日期:2013.6.7
natural product with an intriguing tetracyclic framework, has been achieved. The synthesis features an intramolecularDiels–Alder (IMDA) reaction for the facile construction of the tricyclic [5–7–6] skeleton of caribenol A (1) and a biomimetic oxidation reaction for the formation of the 2-hydroxyfuran-2(5H)-one motif of caribenol A (1) as key steps. This synthetic approach also reveals that the sp2 carbon
Enantio-and diastereoselective synthesis of 4-alpha-alkylcarbovir derivatives 5 were achieved based on Sakai's asymmetric alkylation of beta-keto esters. The key carbocyclic intermediate 14 was synthesized from 8 via an eleven-step sequence. Coupling of 14 with 2-amino-6-chloropurine followed by desilylation and subsequent hydrolysis gave the target compounds 5 in moderate yields. (C) 1998 Elsevier Science Ltd. All rights reserved.