Conformationally Driven Two- and Three-Photon Cascade Processes in the Stereoselective Photorearrangement of Pyrroles

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms Conformationally Driven 2-and 3-Photon Cascade Processes in the Stereoselective Photorearrangement of PyrrolesPaul J. Koovits, Jonathan P. Knowles, Kevin I. Booker-Milburn* School of Chemistry, University of Bristol, Cantock's Close, Bristol, UK, BS8 1TS Supporting Information Placeholder ABSTRACT: A TBSO group has been shown to exert a high degree of stereocontrol during the 2-photon photocycloaddition/rearrangement of N-butenyl pyrroles to complex tricyclic aziridines. Moreover this and other bulky groups have been shown to change the outcome of the reaction, promoting a new 2-photon sequence to tricyclic imines and an unprecedented stereoselective 3-photon sequence to azabicyclo[3.3.1]nonanes.

Photochemical Rearrangements in Heterocyclic Chemistry

“…Photoinduced hydrogen abstraction can be carried out on N‐heterocycles to access interesting compounds. After irradiation of molecule 62 , compound 63 is obtained due to [2 + 2] cycloaddition followed by a photochemical rearrangement (Scheme ) . Longer irradiation triggers 1,5‐HAT leading to the intermediate 64 .…”

Photochemical [2+2] cycloaddition reaction of enone derivatives with 2-silyloxy-1H-pyrrole derivatives

“…[1][2][3][4][5][6][7][8][9] Generally, the photochemical [2+2] oxetane formation reactions are called Paternò-Büchi (PB) reactions, in which furan derivatives have played their significant roles as alkene substrates. [21][22][23] To our best knowledge, even though a series of work concerning intramolecular photochemical [2+2] cycloaddition reaction of pyrrole derivatives have been achieved, [26][27][28]34 very few reports on the intermolecular case have been found till now. [29][30][31][32][33][34] Besides pyrrole derivatives, many examples of the photochemical cyclobutane formations have been reported from pyrrolone [31][32][33][34] and indole [35][36][37][38][39][40][41] compounds.…”

Complex Carbocyclic Skeletons from Aryl Ketones through a Three‐Photon Cascade Reaction

“…A notable two-photon process reported by Booker-Milburn and co-workers [8] enabled the formation of strained aziridines from pyrroles (e.g. 3!4) in a sequence of [2+2] photocycloaddition and photochemical rearrangement.In an ongoing project [9] on photochemical cascade reactions [10] initiated by an ortho photocycloaddition, [6,11] we have now found a facile entry into a yet unexplored class of hydrocarbons with a tetracyclo[5.3.1.0 1,7 0 4,11 ]undec-2-ene core (I, Figure 1). Ring opening of the cyclopropane ring at positions a or b provides access to tricyclo[5.3.1.0 4,11 ]undec-2enes (II) or tricyclo[6.2.1.0 1,5 ]undecanes (III), respectively.…”