Direct Access to MIDA Acylboronates through Mild Oxidation of MIDA Vinylboronates

Abstract

Acylboronate esters/trifluoroborates represent an elusive class of boronates that are of increasing interest for both fundamental study as well as applications at the interface of chemistry and biology. Their preparation has been limited by the use of strongly basic anions, often introduced in multistep reactions. Herein, we demonstrate the facile preparation of acylboronate N-methyliminodiacetyl (MIDA) esters from alkenyl-2-boronate esters through mild dihydroxylation and meta-periodate cleavage. Given the well-known functional-group tolerance of this mild reaction sequence and the availability of alkenyl-2-boronates, this method should greatly increase access to acylboronate MIDA esters.

Alkenyl Boronates: Synthesis and Applications

“…[117] Acylboronates are also accessible by ad ihydroxylation/meta-periodate cleavage process described by Perrin (Scheme27d). [118] Very recently,t he reactivity of tetracoordinate alkenyl boronate complexes by means of 1,2-migration rearrangement has been exploited by several authors (Scheme 28). Morken and co-workersp resented in 2016 ap alladium-catalyzedc onjunctive cross-coupling methodology to obtain secondary alcohols (after oxidation) in high enantiomeric excess using three components:a no rganolithium,a no rganoboronic ester,a nd an organotriflate.…”

Concise Synthesis of Potassium Acyltrifluoroborates from Aldehydes through Copper(I)‐Catalyzed Borylation/Oxidation

“…Recently, our group and that of Perrin reported ozonolysis and dihydroxylation/oxidative cleavage of alkenyl MIDA boronates, respectively, which afford acyl MIDA boronates (Scheme B, a) ,. These approaches are conducted under relatively mild conditions and are suitable for the preparation of highly functionalized acylboronates including the first examples of enantioenriched α‐amino acylboron compounds.…”

“…Acylboron species bearing alkene ( 2 m ) and acetal moieties ( 2 n ) were also obtained in 30–67 % yield. KATs 2 g , 2 m , and 2 n are particularly important since their synthesis through oxidative cleavage of alkenyl MIDA boronates is nontrivial ,. Based on the versatility of this method, we applied it to the preparation of KATs bearing biological molecules, which afforded glucose‐bearing KAT 2 o in 70 % yield.…”

“…Subsequently, we investigated the synthesis of α‐amino acid derived KATs (Table ). This class of compounds is very attractive due to its potential use as a building block in peptide conjugation using KAT ligation , . N ‐Cbz glycinal can be synthesized through the oxidation of N ‐Cbz‐protected 2‐aminoethanol.…”

Preise von CSC und CIC 2019

“…Seine Gruppe entwickelt darüber hinaus auf Organotrifluorboraten basierende Techniken zur 18 F‐Markierung für die PET‐Bildgebung. In einer Angewandte‐Chemie ‐Zuschrift wies er einen direkten Weg zu MIDA‐Acylboronaten durch Oxidation von MIDA‐Vinylboronaten, und in Chemistry—A European Journal nutzte er Organotrifluorborate als Fluoridquelle in Fluordediazonierungen …”