Volume 56, Issue 44 pp. 13618-13622
Communication

A Pyrene-Linked Cavity within a β-Barrel Protein Promotes an Asymmetric Diels–Alder Reaction

Dr. Tomoki Himiyama

Dr. Tomoki Himiyama

Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871 Japan

Search for more papers by this author
Naomasa Taniguchi

Naomasa Taniguchi

Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871 Japan

Search for more papers by this author
Shunsuke Kato

Shunsuke Kato

Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871 Japan

Search for more papers by this author
Dr. Akira Onoda

Corresponding Author

Dr. Akira Onoda

Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871 Japan

Search for more papers by this author
Prof. Takashi Hayashi

Corresponding Author

Prof. Takashi Hayashi

Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka, 565-0871 Japan

Search for more papers by this author
First published: 09 August 2017
Citations: 28

Graphical Abstract

Selectivity by the barrel-load: A reaction cavity with a tethered polycyclic pyrene moiety, which acts as a platform to provide aromatic interactions, is constructed within the rigid scaffold of the β-barrel nitrobindin protein. An asymmetric Diels–Alder reaction between azachalcone and cyclopentadiene proceeds within the reaction cavity of the pyrene-linked nitrobindin with high stereoselectivity.

Abstract

A unique π-expanded reaction cavity tethering a polycyclic moiety which provides a platform for substrate binding was constructed within the robust β-barrel structure of nitrobindin (NB). NB variants with cavities of different sizes and shapes are coupled with N-(1-pyrenyl)maleimide (Pyr) to prepare a series of NB-Pyr conjugates. The orientation of the pyrene moiety is fixed within the cavity by the coupling reaction. The fluorescent quenching analysis of NB-Pyr indicates that azachalcone (aza), which is a dienophile for a Diels–Alder (DA) reaction, is efficiently incorporated within the pyrene-linked reaction cavity by the aromatic interaction. The DA reaction between aza and cyclopentadiene proceeds within the reaction cavity of NB-Pyr in the presence of CuII ion in high yield and high enantio- and regioselectivity.

The full text of this article hosted at iucr.org is unavailable due to technical difficulties.