Chemists Succeed in Synthesis of Aminoalcohols by Utilizing Blue Light

Photosensitized synthesis of protected aminoalcohols.
Credit: WWU – Glorius Group

New method for generating the least accessible form of vicinal aminoalcohols; study published in Nature Catalysis.

Whether in beta-blockers to treat high blood pressure or in natural products, so-called vicinal aminoalcohols are high-quality organic compounds that are found in many everyday products. However, their production is difficult. For a long time, chemists have tried to develop efficient methods of synthesizing them.

In their recent study published in the journal Nature Catalysis, scientists led by Prof. Dr. Frank Glorius of Münster University have found a solution for the production of a special variant of aminoalcohols. “The new method helps to study the properties of the substance and to find applications for these new compounds in the future,” emphasizes Frank Glorius from the Organic Chemistry Institute at Münster University.

Vicinal aminoalcohols can occur in two different variants — called regioisomers — in which the amine and alcohol functional groups exchange positions. Although they are thus very similar, they often have different biochemical properties. Installation of both amine and alcohol groups in one step poses a major challenge. The discovery of the “Asymmetric Amino Hydroxylation Reaction” with which one of the regioisomers can be produced, even rewarded the chemist Barry Sharpless with a Nobel Prize in 2001. However, the other regioisomer cannot be synthesized by similar method and remained a long-standing problem — until now. With the help of the chemists’ new photo-initiated reaction method, the synthesis of the other regioisomer has now also become efficiently possible.

Background and method:

Unactivated alkenes containing a carbon-carbon double bond are known as feedstock chemicals for reaction processes due to their good availability. In general, the installation of both amine and alcohol groups in one step via this carbon-carbon double bond of unactivated alkene is at all times initiated by the amine group, followed by the addition of the alcohol group. As a result, always a particular regioisomer of the vicinal aminoalcohol is formed. Now the scientists have identified a particular class of amine-like compounds that are reactive yet stable enough to allow first the addition of the alcohol group to the carbon-carbon double bond, followed by the addition of the amine group to generate the previously inaccessible opposite regioisomer of the vicinal aminoalcohols.

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