Related Experiment Video
Updated: Apr 18, 2026
08:46
Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of PhosphorusI
Published on: November 22, 2016
8.3K
Reduction of functionalized tertiary phosphine oxides with BH3
Sylwia Sowa1, Marek Stankevič, Anna Szmigielska
1Department of Organic Chemistry, Faculty of Chemistry, Maria Curie Sklodowska University , Gliniana Street 33, Lublin 20-614, Poland.
The Journal of Organic Chemistry
|January 13, 2015
Summary
Researchers developed a new method to convert hydroxyalkylphosphine oxides to hydroxyalkylphosphine-boranes. This facile reduction of the P═O bond occurs under mild conditions with complete inversion of stereochemistry.
Area of Science:
- Organophosphorus Chemistry
- Borane Chemistry
- Stereoselective Synthesis
Background:
- Tertiary hydroxyalkylphosphine oxides are important synthetic intermediates.
- Reduction of the strong phosphorus-oxygen double bond (P═O) typically requires harsh conditions.
- Achieving stereoselective transformations in organophosphorus chemistry remains a challenge.
Purpose of the Study:
- To develop a direct, stereoselective method for converting tertiary hydroxyalkylphosphine oxides to their corresponding borane adducts.
- To investigate the mechanism facilitating the reduction of the P═O bond under mild conditions.
- To establish the stereochemical outcome of the developed transformation.
Main Methods:
- Utilized borane (BH3) as a mild reducing agent for the P═O bond.
- Exploited intramolecular P═O···B complexation, directed by proximal hydroxy groups, to activate the P═O bond.
- Employed two chemical correlations to confirm the stereochemical inversion at phosphorus.
Main Results:
- Successfully developed a direct and stereoselective conversion of hydroxyalkylphosphine oxides to hydroxyalkylphosphine-boranes.
- Demonstrated facile reduction of the strong P═O bond under mild conditions.
- Confirmed complete inversion of configuration at the phosphorus center during the transformation.
Conclusions:
- The developed method offers an efficient route to hydroxyalkylphosphine-boranes with controlled stereochemistry.
- Intramolecular P═O···B complexation is key to enabling the mild reduction of the P═O bond by borane.
- This work provides a valuable tool for synthesizing stereochemically defined organophosphorus compounds.
More Related Videos
Related Concept Videos
03:08Hydroboration-Oxidation of Alkenes
12.8K
In addition to the oxymercuration–demercuration method, which converts the alkenes to alcohols with Markovnikov orientation, a complementary hydroboration-oxidation method yields the anti-Markovnikov product. The hydroboration reaction, discovered in 1959 by H.C. Brown, involves the addition of a B–H bond of borane to an alkene giving an organoborane intermediate. The oxidation of this intermediate with basic hydrogen peroxide forms an alcohol.
12.8K
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
22.2K
Introduction
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
22.2K
02:23Alcohols from Carbonyl Compounds: Reduction
13.3K
Reduction is a simple strategy to convert a carbonyl group to a hydroxyl group. The three major pathways to reduce carbonyls to alcohols are catalytic hydrogenation, hydride reduction, and borane reduction.
Catalytic hydrogenation is similar to the reduction of an alkene or alkyne by adding H2 across the pi bond in the presence of transition metal catalysts like Raney Ni, Pd–C, Pt, or Ru. Aldehydes and ketones can be reduced by this method, often under mild to moderate heat...
Catalytic hydrogenation is similar to the reduction of an alkene or alkyne by adding H2 across the pi bond in the presence of transition metal catalysts like Raney Ni, Pd–C, Pt, or Ru. Aldehydes and ketones can be reduced by this method, often under mild to moderate heat...
13.3K
02:36Regioselectivity and Stereochemistry of Hydroboration
9.9K
A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
9.9K
01:17Carboxylic Acids to Primary Alcohols: Hydride Reduction
5.8K
Carboxylic acids, upon reaction with strong reducing agents such as lithium aluminum hydride followed by hydrolysis, undergo reduction to form primary alcohols.
5.8K
02:15Preparation of Alcohols via Addition Reactions
8.3K
Overview
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
8.3K