New Perspective for Natural Products Synthesis: Concise Synthesis of (+)-Sch 642305 by Chiral Auxiliary Multiuse Methodology
作者:Hiromichi Fujioka、Yusuke Ohba、Kenji Nakahara、Mayuko Takatsuji、Kenichi Murai、Motoki Ito、Yasuyuki Kita
DOI:10.1021/ol702530b
日期:2007.12.1
The synthesis of (+)-Sch 642305 is an example of chiralauxiliary multiuse methodology, which shows a new perspective for the synthesis of compounds with multiple asymmetric centers. Thus, (+)-Sch 642305 was concisely synthesized from the known compound. Every reaction is stereoselective, and the chiral nonracemic hydrobenzoin worked as chiralauxiliary for desymmetrization of diene, as a template for
Asymmetric Synthesis by the Intramolecular Haloetherification Reaction of Ene Acetal: Discrimination of Prochiral Dienes in Cyclohexane Systems
作者:Hiromichi Fujioka、Naoyuki Kotoku、Yoshinari Sawama、Hidetoshi Kitagawa、Yusuke Ohba、Tsung-Lung Wang、Yasushi Nagatomi、Yasuyuki Kita
DOI:10.1248/cpb.53.952
日期:——
A novel asymmetricsynthesis of the cyclohexane derivative functionalized by some substituents has been developed from the diene acetals (1), prepared from the corresponding diene aldehyde and (+)-hydrobenzoin. The treatment of 1 with NBS in the presence of MeOCH2CH2OH predominantly afforded 2 in a stereoselective manner. Subsequent alkylation of the methoxyethoxy group produced the optically active
Concise Asymmetric Total Synthesis of Scyphostatin, a Potent Inhibitor of Neutral Sphingomyelinase
作者:Hiromichi Fujioka、Yoshinari Sawama、Naoyuki Kotoku、Takuya Ohnaka、Takashi Okitsu、Nobutaka Murata、Ozora Kubo、Ruichuan Li、Yasuyuki Kita
DOI:10.1002/chem.200700871
日期:2007.12.17
achieved in a late stage of the total synthesis, and deprotection of the primary alcohol was conducted in the final step. During the synthesis several key reactions were attained: 1) intramolecularbromoetherification of the cyclohexadiene acetal; 2) stereoselective introduction of the tertiary alcohol, 3) deprotection of the acetal function to the aldehyde by combination with silyl triflate/2,4,6-collidine