New perspective for natural products synthesis: concise synthesis of (+)-sch 642305 by chiral auxiliary multiuse
Hiromichi Fujioka1, Yusuke Ohba, Kenji Nakahara
1Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamada-oka, Suita, Osaka 565-0871, Japan. fujioka@phs.osaka-u.ac.jp
Abstract:
The synthesis of (+)-Sch 642305 is an example of chiral auxiliary 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 chiral auxiliary for desymmetrization of diene, as a template for attaining regio- and stereoselective reactions, as an oxygen source at the C4-position, and as a protecting group of hydroxyl functions. Namely, the chiral auxiliary played a role in every step throughout the synthesis. Furthermore, the synthesis contains a new protocol for obtaining alpha'-alkylated enone compounds.
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