Cascading pericyclic reactions: building complex carbon frameworks for natural product synthesis
作者:Steve Arns、Louis Barriault
DOI:10.1039/b700054p
日期:——
Tandem reactions have emerged as powerful strategies to synthesize complex structures, in particular, processes involving pericyclic reactions. This article describes recent advancement by our group in the development of novel tandem pericyclic reactions aimed at constructing diterpene frameworks.
Conservation of the Planar Chiral Information in the Tandem Oxy-Cope/Ene Reaction
作者:Danny Gauvreau、Louis Barriault
DOI:10.1021/jo047916z
日期:2005.2.1
We report the stereoselective synthesis of a Decalin unit using a tandem oxy-Cope/ene reaction. [3,3]-Shift of 1,2-divinyleyclohexenol 18 generates (1E, 3Z, 7E) cyclodecatrien-2-ol 23 which tautomerizes to ketone 21 (Figure 3). The chiral information embedded in 23 is transferred into the newly formed stereogenic carbon C6 in 21. The efficiency of the chirality transfer is a reflection of the difference in the rates of ring inversion versus tautomerization of 23. Ketone 21 undergoes a carbonyl-ene reaction to give Decalin 20. Assuming a rapid equilibrium between macrocyclic diastereomers, the diastereomeric ratio of the transannular ene reaction is governed by the Curtin-Hammett principle. Analysis of the conservation of the planar chiral information in the tandem oxy-Cope/ene reaction is presented.