Photoinduced Vinylcyclopropane-Cyclopentene Rearrangement (Photo-VCP-CP): A Methodology for Chiral Bicyclo[3.2.0] heptenes and their Application in Natural Product Syntheses^#

(+)-_Δ ³-Carene serves as a useful source material in generating chiral bicyclo[3.2.0]heptenes on a preparative scale employing photochemical vinylcyclopropane-cyclopentene rearrangement as a convenient method. These chiral units are useful as key intermediates in asymmetric synthesis of different natural products known for significant biological activity. Adaptation of spirocyclic VCP-CP - oxidative scission sequence provides a short way for a three carbon intercalation of cycloalkanones to cyclic 1,5-diones. The potential of this sequence in the synthesis of some important carbon frameworks is highlighted. 1. Introduction 2. Photochemical Approach to chiral bicyclo[3.2.0]heptenes 3. Natural Product Synthesis 3.1 (-)/(+)-_Δ ⁹⁽¹²⁾-Capnellene 3.2 (+)-Lineatin 3.3 (±)-Grandisol 4. Three Carbon Ring Expansion of Cycloalkanones to 1,5-Diones 4.1 Bicyclo[m.3.0]bridged alkenes 4.2 Taxane skeleton 5. Other Studies 6. Conclusions