A new tool to create chemical complexity from fatty acids

Date:
August 20, 2020
Source:
Hokkaido University
Summary:
A new catalyst design enables unprecedented control over the
modification of fatty acid derivatives that opens the door to
creating useful substances in a green and efficient manner.



FULL STORY ==========================================================================
A new catalyst design enables unprecedented control over the modification
of fatty acid derivatives that opens the door to creating useful
substances in a green and efficient manner.


========================================================================== Hokkaido University WPI-ICReDD researchers developed a modular
catalyst that can accurately modify fatty acid derivatives in a hitherto inaccessible position. This enables the efficient production of valuable compounds from a renewable bioresource, whereas before we had to either
rely on petroleum- derived resources or use complicated and costly
methods.

Many pharmaceuticals and plastics consist of a backbone that is
essentially a chain of carbon atoms with modifications within their
hydrocarbon framework.

For their production, fatty acids are attractive raw material because
they are easily accessible, renewable natural resources that consist of
a chain of carbon atoms attached to a functional group called "carboxyl
group." However, our ability to modify these chains has so far been
limited to carbon atoms only one or two atoms away from the carboxyl
group. Professor Masaya Sawamura of Hokkaido University's Institute
for Chemical Reaction Design and Discovery (WPI-ICReDD) explains,
"The chemical materials obtained in this way are limited to those with
fairly simple structures, and in order to synthesize useful compounds, multi-step processes are necessary." Building upon previous studies, Sawamura's group constructed a catalyst that consists of an iridium
atom at its core and various modules that ensure that a fatty acid
derivative -- fatty acid amide or ester in this case -- is precisely
positioned in such a way that the C-H bond located three carbons away
from the carboxyl group is modified. Moreover, while every C-H bond in a
fatty acid derivative can be modified in two ways, giving compounds that
are mirror images of one another, the catalyst developed by the team
produces only one of the two possible products, which is an important
attribute especially for drug development. To increase the breadth of
possible modifications further, the researchers try to use different
modules in their catalyst to change the way the substrate is positioned
in the catalyst to allow different modifications.

In their article published in Science, the team demonstrated that their approach works with various substrates and can produce a large range of
useful derivatives. In addition, they used quantum chemical calculations
to investigate the precise structure and function of their catalyst
driving the observed reactivity and selectivity. The results confirmed
that the catalyst has a deep pocket that binds the substrate through interactions between one of its subunits and the carbonyl group of the substrate, and keeps it in place to facilitate the specific reaction --
a feature analogous to natural enzymes.

"The modular catalyst allowed the site-selective modification of fatty
acid amides and esters, some of which are bioactive compounds. This
simple, modular, and broadly applicable catalytic system allows the introduction of structural and chemical complexity to the hydrocarbon
chain of readily available feedstock chemicals," says Ronald Reyes of the research team. Central to the success of these endeavors is a combination
of experiments and computation. Sawamura says, "The accumulation of experimental knowledge is a source of great inspiration, but with the
support of computer chemistry we can bring this to fruition in the
near future."

========================================================================== Story Source: Materials provided by Hokkaido_University. Note: Content
may be edited for style and length.


========================================================================== Related Multimedia:
*
YouTube_video:_A_New_Tool_to_Create_Chemical_Complexity_from_Fatty_Acids ========================================================================== Journal Reference:
1. Ronald L. Reyes, Miyu Sato, Tomohiro Iwai, Kimichi Suzuki,
Satoshi Maeda,
Masaya Sawamura. Asymmetric remote C-H borylation of aliphatic
amides and esters with a modular iridium catalyst. Science, 2020;
369 (6506): 970- 974 DOI: 10.1126/science.abc8320 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/08/200820143234.htm

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