Cascading pericyclic reactions: building complex carbon frameworks for natural product synthesis

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.

Synthesis of the C7-C15 trans decalin portion of the natural antibiotic tetrodecamycin

[reaction: see text] The tandem oxy-Cope/ene/Claisen rearrangement has been developed in our laboratory as a powerful method for rapid construction of complex Decalin cores. Herein, we describe the use of this method to generate the Decalin core of the natural antibiotic tetrodecamycin (1) bearing six contiguous stereocenters.

Highly Efficient Transfer of Chirality from Macrocyclic Conformation in the Tandem Oxy-Cope/Claisen/Ene Reaction

We report three highly stereoselective pericyclic reactions occurring in cascade leading to the synthesis of Decalins skeletons possessing two contiguous quaternary centers. The tandem reaction is triggered by an oxy-Cope rearrangement to create in situ a 10-membered ring enol ether macrocyle 6, which immediately rearranges via a Claisen [3,3] shift to the corresponding E-cyclodec-6-en-1-one 7. The latter spontaneously cyclizes via a transannular ene reaction to produce Decalin 5. Analysis of the mechanism with respect to the origin of the high diastereoselectivity of the tandem oxy-Cope/Claisen/ene reaction is presented.