20 Questions
What is the temperature range for the reduction using NaBH4?
0-25 oC
What are some solvents commonly used for the reduction with NaBH4?
EtOH, MeOH, Dimethoxy ethane (DME)
Which reagents are used for the selective reduction of ketones in the presence of aldehydes?
NaBH4, CeCl3
What is the mechanism for the reduction using NaBH4?
RCHO, RCOR, RCOCl, R2C=NR
What is the purpose of using NaBH4 in the Luche reduction?
To reduce the carbonyl group to an alcohol
What is the role of CeCl3 in the Luche reduction?
It acts as a good Lewis acid and is highly oxophilic
What reagents are used for the reduction of imines?
NaBH4, H2O
Why can't NaBH4 reduce RCN unless Meerwein’s salt is used?
NaBH4 alone is unable to reduce RCN, unless Meerwein’s salt (Me3O+BF4-) is used
Which reagent is more reactive than NaBH4 but milder than LiAlH4 in ether?
LiBH4
What is the typical substrate for the reduction using LiBH4?
Aldehydes, ketones, esters, carboxylic acids, and acid chlorides
What is the primary reason for the higher reactivity of LiBH4 compared to NaBH4?
Greater Lewis acid strength of Li+
At what pH does NaBH3CN reduce aldehydes and ketones efficiently?
pH 3-4
What is the main drawback of NaCNBH3 in some cases?
Sometimes strong acids can release HCN from NaCNBH3
What do boranes attack due to their highly electrophilic nature?
The most electron rich center
In the reduction of carboxylic acids to primary alcohols using BH3, what functional groups can be present in the presence of esters?
Nitro and cyano groups
What is the primary function of Zn(BH4)2 in the chelation control model?
Good for base sensitive groups
What is the primary difference between borohydrides and boranes in terms of charge and reactivity?
Borohydrides are negatively charged and nucleophilic, while boranes are neutral and electrophilic.
What is the primary function of LiBHEt3 (Superhydride) in reduction reactions?
Very reactive hydride source, reducing ketones, aldehydes, esters, epoxides, and C-X bonds
What is the role of NaBH4/NiCl2 in reduction reactions?
It is used for the reduction of aryl nitro compounds to aryl amines.
What is the primary use of 9-BBN in reduction reactions?
Preparation of Zn(BH4)2
Study Notes
- Organo Chemistry involves the study of carbon-containing compounds and their reactions.
- Boron-based reagents are commonly used in Organo Chemistry reductions.
- Boron reagents include NaBH4, NaBH4/CeCl3, NaBH4/NiCl2, LiBH4, Boranes, NaCNBH3, Zn(BH4)2, Alkyl borohydrides.
- NaBH4 is a common reducing agent in Organo Chemistry, used for reducing ketones and aldehydes. It requires 0.25 equiv. and is most effective in EtOH.
- CeCl3 is used as a Lewis acid catalyst in the reduction of ketones in the presence of aldehydes, improving selectivity and yield.
- LiBH4 is more reactive than NaBH4 but milder than LiAlH4 in ether. It can reduce esters and lactones efficiently.
- NaBH3CN is a boron-based reagent used in reductive aminations, particularly in the reduction of iminium ions.
- Boranes are highly electrophilic, attacking the most electron-rich centers. They reduce carboxylic acids to primary alcohols and can be used for epoxide openings.
- Zn(BH4)2 is prepared by reacting ZnCl2 with NaBH4 in ether and is used for reducing base-sensitive groups.
- Alkyl borohydrides are selective reducing agents, with different types, such as Superhydride, having unique properties and uses.
- LiBHEt3 (Superhydride) is a very reactive hydride source that is used to reduce ketones, aldehydes, esters, and C-X bonds.
- Borohydrides are negatively charged and nucleophilic, while boranes are neutral and electrophilic. Boron valence shell completes an octet in both cases.
- NaBH4/NiCl2 is used for reduction of Ar NO2 to Ar NH2, Ar NO to Ar NH2, and Ar C N OH to Ar H2 C NH2. It is used in the presence of Zn(BH4)2 for base-sensitive groups.
- Zn(BH4)2 is prepared by reacting ZnCl2 with NaBH4 in ether. It is a good reducing agent for base-sensitive groups.
- Alkyl borohydrides have selective reducing properties, with different types having different applications.
- LiBHEt3 (Superhydride) is a very reactive hydride source that is used to reduce a variety of functional groups.
- Borohydrides and boranes have different properties, with borohydrides being negatively charged and nucleophilic, while boranes are neutral and electrophilic. Boron valence shell completes an octet in both cases.
- NaBH4 is used for reducing ketones and aldehydes, with CeCl3 used as a Lewis acid catalyst for improving selectivity.
- LiBH4 is a more reactive reducing agent than NaBH4 and is used for reducing esters and lactones efficiently.
- NaBH3CN is a boron-based reagent used in reductive aminations, particularly in the reduction of iminium ions.
- Boranes are highly electrophilic and attack the most electron-rich centers. They can be used for the reduction of carboxylic acids and the opening of epoxides.
- Zn(BH4)2 is prepared by reacting ZnCl2 with NaBH4 in ether and is used as a reducing agent for base-sensitive groups.
- Alkyl borohydrides are selective reducing agents with different types having unique properties and applications.
- LiBHEt3 (Superhydride) is a reactive hydride source used for reducing a variety of functional groups.
- Borohydrides are negatively charged and nucleophilic, while boranes are neutral and electrophilic. Boron valence shell completes an octet in both cases.
- Zn(BH4)2 is prepared from ZnCl2 and NaBH4 in ether and is used for reducing base-sensitive groups.
- Alkyl borohydrides are selective reducing agents with different types having different applications.
- LiBHEt3 (Superhydride) is a reactive hydride source used for reducing a variety of functional groups.
- Borohydrides are negatively charged and nucleophilic, while boranes are neutral and electrophilic. Boron valence shell completes an octet in both cases.
- NaBH4 is used for reducing ketones and aldehydes in the presence of CeCl3 for improved selectivity.
- LiBH4 is a more reactive reducing agent than NaBH4, used for reducing esters and lactones efficiently.
- NaBH3CN is a boron-based reagent used for reductive aminations in the reduction of iminium ions.
- Boranes are highly electrophilic and attack the most electron-rich centers, used for reducing carboxylic acids and opening epoxides.
- Zn(BH4)2 is prepared from ZnCl2 and NaBH4 in ether and is used for reducing base-sensitive groups.
- Alkyl borohydrides are selective reducing agents, with different types having different applications.
- LiBHEt3 (Superhydride) is a reactive hydride source used for reducing a variety of functional groups.
- Borohydrides are negatively charged and nucleophilic, while boranes are neutral and electrophilic. Boron valence shell completes an octet in both cases.
- NaBH4 is used for reducing ketones and aldehydes in the presence of CeCl3 for improved selectivity.
- LiBH4 is a more reactive reducing agent than NaBH4, used for reducing esters and lactones efficiently.
- NaBH3CN is a boron-based reagent used for reductive aminations, particularly in the reduction of iminium ions.
- Boranes are highly electrophilic and attack the most electron-rich centers, used for reducing carboxylic acids and opening epoxides.
- Zn(BH4)2 is prepared from ZnCl2 and NaBH4 in ether and is used for reducing base-sensitive groups.
- Alkyl borohydrides are selective reducing agents, with different types having different applications.
- LiBHEt3 (Superhydride) is a reactive hydride source used for reducing a variety of functional groups.
- Borohydrides are negatively charged and nucleophilic, while boranes are neutral and electrophilic. Boron valence shell completes an octet in both cases.
- NaBH4 is used for reducing ketones and aldehydes, with CeCl3 used as a Lewis acid catalyst for improved selectivity.
- LiBH4 is a more reactive reducing agent than NaBH4 and is used for reducing esters and lactones efficiently.
- NaBH3CN is a boron-based reagent used in reductive aminations, particularly in the reduction of iminium ions.
- Boranes are highly electrophilic and attack the most electron-rich centers, used for reducing carboxylic acids and opening epoxides.
- Zn(BH4)2 is prepared from ZnCl2 and NaBH4 in ether and is used for reducing base-sensitive groups.
- Alkyl borohydrides are selective reducing agents, with different types having different applications.
- LiBHEt3 (Superhydride) is a reactive hydride source used for reducing a variety of functional groups.
- Borohydrides are negatively charged and nucleophilic, while boranes are neutral and electrophilic. Boron valence shell completes an octet in both cases.
- Borohydrides are negatively charged and nucleophilic, while boranes are neutral and electrophilic. Boron valence shell completes an octet in both cases.
- Boron-based reagents, including borohydrides and boranes, are widely used in Organo Chemistry reductions.
- NaBH4 is used for reducing ketones and aldehydes, with CeCl3 used as a Lewis acid catalyst for improved selectivity.
- LiBH4 is a more reactive reducing agent than NaBH4, used for reducing esters and lactones efficiently
Test your knowledge of organo chemistry reduction using boron-based reagents including NaBH4, NaBH4/CeCl3, NaBH4/NiCl2, LiBH4, boranes, NaCNBH3, Zn(BH4)2, and alkyl borohydrides. Explore topics such as temperature, solvents, substrates, and mechanisms.
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