An Insight into Selective Olefin Bond Functionalization of Cyclodienes through Nitrile Oxide 1,3‐Dipolar Cycloadditions

Abstract

Selective functionalizations of the ring olefin bond of various commercial cyclodienes through nitrile oxide dipolar cycloaddition is described. Nitrile oxides were generated from primary nitroalkanes by Mukaiyama's method. Besides regioselectivity, the dipolar cycloadditions have been performed in view of selectivity of the ring olefin bonds. The cycloalkenefused isoxazoline products were easily converted through ring opening and cross metathesis into valuable dialkenylated heterocycles.

Selective Functionalization of Norbornadiene Through Nitrile Oxide Cycloaddition/Ring‐Opening/Cross‐Metathesis Protocols

“…We have carried out the synthesis of various novel functionalized isoxazoline-fused cyclopentanes bearing multiple stereogenic centers and studied the nature of their chemical transformations in view of stereo-and regioselectivity as well as chemoselectivity across substrate control. For this purpose, first, functionalization of norbornadiene through nitrile oxide cycloaddition was performed taking also into consideration our earlier findings on selective nitrile oxide cycloadditions [6,7] to access to cyclodienes with different ring sizes. For the generation of nitrile oxide, Mukayama's method has been applied [7] when the reaction of a nitroalkane, di-tert-butyl dicarbonate, and DMAP furnished the desired dipole which reacted with the C=C bond in order to furnish the desired isoxazoline-fused derivatives.…”

Diversity‐oriented Functionalization of Cyclodienes Through Selective Cycloaddition/Ring‐opening/Cross‐metathesis Protocols; Transformation of a “Flatland” into Three‐dimensional Scaffolds With Stereo‐ and Regiocontrol

“…In a recent work some readily available commercial cyclodienes were selectively transformed through nitrile oxide 1,3‐dipolar cycloaddition into the corresponding cycloalkene‐fused isoxazolines (Scheme ) …”