Photocatalytic E→Z Isomerization of β-Ionyl Derivatives

Livingstone, Keith and Tenberge, Marius and Pape, Felix and Daniliuc, Constantin G. and Jamieson, Craig and Gilmour, Ryan (2019) Photocatalytic E→Z Isomerization of β-Ionyl Derivatives. Organic Letters, 21 (23). pp. 9677-9680. ISSN 1523-7060

[thumbnail of Livingstone-etal-OL-2019-Photocatalytic-E-Z-isomerization-of-B-ionyl-derivatives]
Preview
 Text (Livingstone-etal-OL-2019-Photocatalytic-E-Z-isomerization-of-B-ionyl-derivatives)
Livingstone_etal_OL_2019_Photocatalytic_E_Z_isomerization_of_B_ionyl_derivatives.pdf
Accepted Author Manuscript
Download (638kB)| Preview

    Abstract

    An operationally simple E → Z isomerization of activated dienes, based on the β-ionyl motif intrinsic to retinal, is reported using inexpensive (−)-riboflavin (vitamin B2) under irradiation at 402 nm. Selective energy transfer from photoexcited (−)-riboflavin to the starting E-isomer enables geometrical isomerization. Since the analogous process with the Z-isomer is inefficient, microscopic reversibility is circumvented, thereby enabling a directional isomerization to generate the contra-thermodynamic product (up to 99% yield, up to 99:1 Z/E). Prudent choice of photocatalyst enables chemoselective isomerization to be achieved in both inter- and intramolecular systems. The principles established from this study, together with a molecular editing approach, have facilitated the development of a regioselective isomerization of a truncated triene based on the retinal scaffold.

    ORCID iDs

    Livingstone, Keith, Tenberge, Marius, Pape, Felix, Daniliuc, Constantin G., Jamieson, Craig ORCID logoORCID: https://orcid.org/0000-0002-6567-8272 and Gilmour, Ryan;
    CORE (COnnecting REpositories)