Asymmetric Reduction of Diynones and the Total Synthesis of (S)-Panaxjapyne A
摘要:
The asymmetric transfer hydrogenation of a series of diynones has been achieved in high conversion and enantiomeric induction. When R-1 is a phenyl group, a competing alkyne reduction takes place; however, when R-1 is an alkyl group, this side-reaction is not observed. The application of the reduction to the total synthesis of the natural product (S)-panaxjapyne A in high enantiomeric excess is described.
A One-Pot Synthesis and Functionalization of Polyynes
作者:Yasuhiro Morisaki、Thanh Luu、Rik R. Tykwinski
DOI:10.1021/ol0528888
日期:2006.2.1
[reaction: see text] A one-pot synthesis and derivatization of diynes and triynes is reported. The polyyne framework is formed from a dibromoolefin precursor based on a carbenoid rearrangement, and the resulting Li-acetylide is then trapped in situ with an electrophile to provide functionalized di- and triynes. Alternatively, transmetalation of the Li-acetylide intermediate provides either the Zn-
One-Pot Formation and Derivatization of Di- and Triynes Based on the Fritsch−Buttenberg−Wiechell Rearrangement
作者:Thanh Luu、Yasuhiro Morisaki、Nina Cunningham、Rik R. Tykwinski
DOI:10.1021/jo701810g
日期:2007.12.1
A divergent, one-pot synthesis of functionalized polyynes has been developed. Beginning with the appropriately substituted dibromoolefinic precursor, a carbenoid Fritsch−Buttenberg−Wiechell (FBW) rearrangement is used to generate the lithium acetylide of a conjugated polyyne framework, and subsequent trapping with carbon-based electrophiles provides for in situ formation of a wide range of di- and