Concise Total Synthesis of (±)-Cephalotaxine via a Transannulation Strategy: Development of a Facile Reductive oxy-Nazarov Cyclization
作者:Wei-Dong Z. Li、Wei-Guo Duo、Cheng-Han Zhuang
DOI:10.1021/ol201390r
日期:2011.7.1
A concise totalsynthesis of (±)-cephalotaxine (1) has been achieved from dioxolanone derivative 15 via a transannulation strategy. The key transformation is a facile reductive oxy-Nazarov cyclization as illustrated above, involving presumably a tethered 1,2-oxidopentadienyl cation species 7a or 7b, which represents a new variant of the oxy-Nazarov cyclization and constitutes an effective, regio- and
The cycloinsertion of cyclohexyne into a pentalene has provided access to the carbon scaffold of the guanacastepenes in nine steps. A late‐stage diversifying oxidation of the core structure enabled the synthesis of guanacastepene N and the first total synthesis of guanacastepene O.
The present invention relates to novel GPR 40 agonists of the general formula (I), their tautomeric forms, their stereoisomers, their pharmaceutically acceptable salts, pharmaceutical compositions containing them, methods for their preparation, use of these compounds in medicine and the intermediates involved in their preparation.
The present invention relates to novel GPR 40 agonists of the general formula (I), their tautomeric forms, their stereoisomers, their pharmaceutically acceptable salts, pharmaceutical compositions containing them, methods for their preparation, use of these compounds in medicine and the intermediates involved in their preparation.