Chan-Evans-Lam Amination of Boronic Acid Pinacol …

C-B Bond Formation > Synthesis of boronic acids and boronates > Synthesis of arylboronic ..
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Synthesis of Boronic Acids and Boronate ..

The Petasis reaction is very relevant to synthetic targets containing a 1,2-amino alcohol motif, particularly since the corresponding starting materials are α-hydroxyaldehydes that may be readily available as aldose sugars. Several syntheses have applied the Petasis reaction to the synthesis of natural products containing 1,2-amino alcohols. One route to calystegine B4 started from the aldohexose D-lyxose, which was subjected to Petasis reaction with benzylamine and ()-β-styrenylboronic acid to afford a -1,2-amino alcohol in good yield and high diastereoselectivity. This synthetic intermediate was carried on to the natural product (Eq. 13).

Chan–Evans–Lam Amination of Boronic Acid Pinacol (BPin) Esters: Overcoming the Aryl Amine Problem
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Catalyzed C–C Coupling of Aryl Iodides and Boronic Acids

Forward thinking researchers are increasingly looking to boron containing molecules. This short paper has discussed several applications and uses of boronic acids. All indications point to continued growth in the use of boronic acids. Even as this article is being written more reports are emerging. From its humble beginnings in 1865, to the meteoric rise resulting from Suzuki and Miyaura’s reaction, organoboron compounds are fast becoming compounds used for everything from starting materials to approved drugs. Frontier Scientific stands ready to help researchers create novel chemistries. Give the people at Frontier a call today; the future awaits.

Novel Petasis boronic acid reactions with indoles: synthesis of indol-3-yl-aryl-acetic acids
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We report the copper(II)-catalyzed conversion of organoboron compounds into the corresponding azide derivatives. A systematic series of phenylboronic acid derivatives is evaluated to examine the importance of steric and electronic effects of the sub-stituents on reaction yield as well as functional group compatibility. Heterocyclic substrates are also shown to participate in this mild reaction while compounds incorporating B-C(sp3) bonds are unreactive under the reaction conditions. The copper(II)-catalyzed boronic acid-azide coupling reaction is further extended to both boronate esters and potassium organotrifluoroborate salts. The method described herein complements existing procedures for the preparation of aryl azides from the respective amino, triazene, and halide derivatives and we expect that it will greatly facilitate copper- and ruthenium-catalyzed azide-alkyne cycloaddition reactions for the preparation of diversely functionalized 1-aryl- or 1-heteroaryl-1,2,3- triazoles derivatives.

Preparation of Aryl Boronic Acids under Ultrasonication
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Arylboronic acid or boronate synthesis - Organic …

The boronic acid Mannich reaction (or Petasis reaction) is a three-component coupling reaction involving boronic acids or boronate esters, carbonyl compounds, and amines. Like the traditional Mannich reaction, the electrophile of the Petasis reaction is an iminium ion generated from the amine and carbonyl compound. Iminium ions including a nearby Lewis basic group react with boron-based nucleophiles to afford α-allyl, -alkenyl, -aryl, and -alkynyl amines.

22/01/2014 · Abstract

Multicomponent reactions are efficient transformations that involve the coupling of three or more reactants in an atom-economical manner. In 1993, Petasis reported that secondary amines and paraformaldehyde react with 1-alkenyl boronic acids in a one-pot, multicomponent reaction to afford allylic amines. Since this initial report, additional studies have shown that the Petasis reaction is quite general: a variety of amines and carbonyl compounds react with allylic, alkenyl, aryl, and alkynyl boronic acids, boronate esters, or trifluoroborates to yield products of addition of the organoboron species across an iminium ion generated (Eq. 1).

Alkylboronic acid or boronate synthesis - Organic …

N2 - We report the copper(II)-catalyzed conversion of organoboron compounds into the corresponding azide derivatives. A systematic series of phenylboronic acid derivatives is evaluated to examine the importance of steric and electronic effects of the sub-stituents on reaction yield as well as functional group compatibility. Heterocyclic substrates are also shown to participate in this mild reaction while compounds incorporating B-C(sp3) bonds are unreactive under the reaction conditions. The copper(II)-catalyzed boronic acid-azide coupling reaction is further extended to both boronate esters and potassium organotrifluoroborate salts. The method described herein complements existing procedures for the preparation of aryl azides from the respective amino, triazene, and halide derivatives and we expect that it will greatly facilitate copper- and ruthenium-catalyzed azide-alkyne cycloaddition reactions for the preparation of diversely functionalized 1-aryl- or 1-heteroaryl-1,2,3- triazoles derivatives.

Palladium-Catalyzed, Direct Boronic Acid Synthesis …

An important feature of the boronic acid Mannich reaction is its requirement for a proximal Lewis basic group in the carbonyl component—it has been proposed that the Lewis base activates and orients the organoboron species prior to addition. The mechanism of the reaction is not known with certainty, but a number of observations point to the importance of a zwitterionic intermediate in the mechanism (see Mechanism and Stereochemistry below). Many boronic acid Mannich reactions of chiral carbonyl compounds are diastereoselective, and enantioselective variants of the reaction based on chiral biphenols have been developed. The reaction is applicable to a broad array of substrates: the carbonyl component may be an α-hydroxyaldehyde, salicylaldehyde, or glyoxylic acid; the amine may be primary, secondary, or ammonia; and the organoboron species may be an allyl-, alkenyl-, aryl-, or alkynylboronic acid or boronate ester. The reaction has been applied to several syntheses of natural products and is particularly appealing for syntheses starting from aldose sugars, which bear an α-hydroxyaldehyde group.