A general synthesis of unnatural α-amino acids by iron-catalysed olefin–olefin coupling via generated radicals (original) (raw)
* Corresponding authors
a A. N. Nesmeyanov Institute of Organoelement Compounds of Russian Academy of Sciences, Vavilova Str. 28, 119991 Moscow, Russian Federation
E-mail: larionov@ineos.ac.ru
b Department of Inorganic Chemistry, Peoples’ Friendship University of Russia (RUDN University), Miklukho-Maklaya Str. 6, 117198 Moscow, Russian Federation
c Dmitry Mendeleev University of Chemical Technology of Russia, Miusskaya sq. 9, 125047 Moscow, Russian Federation
d Plekhanov Russian University of Economics, Stremyanny per. 36, 117997 Moscow, Russian Federation
Abstract
Herein, we report an efficient and practical protocol for the asymmetric synthesis of unnatural α-amino acids (AAs) with γ-tertiary and quaternary carbon centres via selective intermolecular iron-catalysed olefin–olefin coupling of a chiral Ni(II) complex of dehydroalanine Schiff base 2 ((S)-BPB-Ni-Δ-Ala) with different olefins. In all successful reactions, diastereomeric nickel complexes were typically obtained in a ratio of up to dr > 20 : 1. The desired products were isolated in 42–93% yields (18 examples). Exemplarily, the three Ni(II) complexes obtained were decomposed with aqueous HCl and the target unnatural α-amino acids were isolated with excellent enantioselectivities and yields of up to 83%. The chiral auxiliary (BPB = 2-(_N_-benzylprolyl)aminobenzophenone) was readily recycled and reused for the synthesis of the starting chiral Ni(II) complex 2. The developed protocol provided a facile access to the analogues of glutamic acid, leucine and phosphinothricin.
You have access to this article
Please wait while we load your content... Something went wrong. Try again?
Supplementary files
Article information
DOI
https://doi.org/10.1039/C9QO00108E
Article type
Research Article
Submitted
23 Jan 2019
Accepted
15 Feb 2019
First published
18 Feb 2019
Download Citation
Org. Chem. Front., 2019,6, 1094-1099
Permissions
A general synthesis of unnatural α-amino acids by iron-catalysed olefin–olefin coupling via generated radicals
V. A. Larionov, N. V. Stoletova, V. I. Kovalev, A. F. Smol'yakov, T. F. Savel'yeva and V. I. Maleev,Org. Chem. Front., 2019, 6, 1094DOI: 10.1039/C9QO00108E
To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.
If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.
If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.
Read more about how to correctly acknowledge RSC content.