General Reactions of Carbonyl Compounds

______________ results in a decrease ini the number of C-Z bonds ( usually C-O bonds) or an increase in the number of C-H bonds.

Reduction

Aldehydes are oxidized selectively in the presence of other functional groups using________ reagent;Silver(I) oxide in aqueous ammonium hydroxide (Ag2O in NH4OH). Oxidation with this reagent provides a distinct color change, because the Ag+ reagent is reduced to solver metal (Ag), which precipitates out of solution.

Tollens

__________ are organometallic compounds prepared by an acid-base reaction of an alkyne with a base such as NaNH2 or NAH. We can think of these compounds as organosodium reagents. These are considered ionic rather than polar covalent because sodium is even more electropositive than lithium. An acid-base reaction can also be used to prepared sp hybridized Organolithium compounds, Treatment of a terminal alkyne with CH3Li affords a lithium acetylide

Acetylide Anions

carbonyl compounds that also contain N-H or O-H bond undergo an __________ reaction with organometallic reagents, not nucleophilic addition. Hence the need for protecting groups.

Acid-base

Oxidation of aldehydes to ____________.

Carboxylic acids

What are the selective reducing agents:

DIBAL,LiALH[OC(CH3)3]3

R-X+Mg---> R-Mg-X. With magenesium , the metal inserts in the carbon-halogen bond, forming the Grignard reagent. Grignard reagents are usually prepared in Ch3CH2OCH2CH3 or diethyl ether solvent. This is preperation of an ____________ reagent.

Grignard

Nucleophilic addition with aldehydes and ketones occurs with two different nucleophiles: carbanions, and __________.

Hydrides

Carboxylic acids are reduced to alcohols with what strong reducing agent?

LiAlH4

Hydride reduction of an achiral ketone with LiAlH4 or _______ gives a racemic mixture of two alcohols when a new stereogenic center is formed

NaBH4

Aldehydes and ketones undergo_____________ addition reactions.

Nucleophilic

Organocuprates are prepared from____________ reagents by reaction with a Cu+ salt, often CuI. 2R-Li+CuI-->R2Cu-Li+LiI

Organolithium

___________ results in an increase in the number of C-Z bonds; Z being the electronegative atom (usually C-O bonds) or a decrease in the number of C-H bond.

Oxidation

A common O-H protecting group is _____

TBDMS

Reduction of carboxylic acid derivatives

The reduction of carboxylic acids and their derivatives gives a variety of products, depending on the identity of Z and the nature of the reducing agent. The usual products are aldehydes or primary alcohols.

LiAlH4 reduction of amide forms__________. Both C-O bonds are reduced to C-H bonds. Amide reduction proceeds with formation of an intermediate __________, a compound containing a C-N double bond, which is then further reduced to an amine.

amines,imine

organometallic reagents are strong __________ that readily abstract a proton from water to form hydrocarbons.

bases

alpha-beta unsaturated carbonyl compounds: Organolithium and Grignard reagents afford 1,2 addition products meaning they add to the _________ thus forming an allylic alcohol .while organocuperates produce 1,4 addition products or conjugate addition where the nucleophile attacks the beta carbon ( where the double bond is located) forming a carbonyl compound

carbonyl group

aldehydes can be oxidized to____________using a variety of oxidizing agents such as CrO3,Na2Cr2O7,K2Cr2O7,KMnO4,Cr6+. Because ketones have no H on the carbonyl carbon they do not undergo this oxidation reaction

carboxylic acids

Grignards react with CO2 to afford__________. this reaction is called carboxylation,

carboxylic acids.

Organometallic reagents are also strong________ that react with electrophilic carbon atoms to form new carbon-carbon bonds.

nucleophiles

Organometallic reagents react as if they wwere free carbonaninons; carbon bears a partial negative charge; so the reagents react as bases _______

nucleophiles

Aldehydes and ketones react with______ to form addition products by the two-step process : Nucleophilic attack followed by___________. The elements of H and Nu are added across the pi bond.

nucleophiles,protonation

Organocuperates have less polar carbon-metal bonds than Grignard (organomagenesium) and organolithium reagents( these two metals; Mg and Li are more electropositive) and therefore Organocuperates are less reactive. Although organocuperates contain two alkyl groups bonded to copper, only______ R group is utilized in reaction.

one

R--X+2Li---> R--Li+LiX with lithium, the halogen and metal exchange to form the organolithium reagent. This is preperation of an ______________ reagent

organolithium

___________________ reagents contain a carbon atom bonded to a metal. The more polar the carbon-metal bond, the more reactive this kind of reagent is.

organometallic

acid chlorides and ester can be reduced to either aldehydes or alcohols depending on the ___________ agent

reducing

Carbonyl compounds that contain leavings groups undergo nucleophilic ______________.

substitution

Carbonyl compounds with leaving groups react with nucleophiles to form ( substitution/addition) products?

substitution

Both esters and acid chlorides form ________ alcohols when treated with two equivalents of either Grignard or Organolithiumm reagents. in the mechanism the first equivalent converts the ester or acid chloride to a ____ and then the second equivalent to the final product.

tertiary, ketone. Organolithiumm and Grignard reagents always afford tertiary alcohols when they react with esters andd acid chlorides .

A C=C is reduced faster than a C=O with H2(Pd-C) A C=O is readily reduced with NaBH4 and LiAlH4, but a C=C is inert.

true

The better the leaving group Z, the more reactive RCOZ is in nucleophilic acyl substitution. Acid chlorides have the best leaving group--Cl- (True/ False) Amides have the worst leaving group( True/False)

true,true Cl is electronegative and have weak electron withdrawing inductive effect while NH2, the N has a pair of lone pair of electrons that it can donate and therefore is more basic thus making it a weak leaving group. The best leaving group is the weakest base; base donates electrons however you want leaving groups to hold onto electrons to leave.

One enantiomer can be formed selectively from the reduction of a carbonyl group provided a chiral reducing agent such as oxazaborolidine (CBS) it has one stereogenic center and thus two eneatintiomers. R-CBS and S-CBS and attack with R-CBS forms S-alcohol and attack with S-CBS forms R-alcohol .

....

NaBH4 selectively reduced aldehydes and ketones in the presence of most other functional groups. LiAlH4 is a stronger reducing agent because the Al--H bonds are more polar. Reduction with NaBH4 are typically carried out in_________ as solvent. LiAlH4 reduces aldehydes and ketones and many other functional groups.

CH3OH

The net result of nucleophilic substitution is Nu replaces Z-- a nucleophilic substitution reaction. This reaction is often called nucleophilic_____- substitution to distinguish it from the nucleophilic substitution reactions at sp3 hybridized carbons. Carboanions and Hydrides are also used as nucleophiles in this reaction.

acyl

Treatment of an aldehyde or ketone with either a Organolithium or Grignard reagent followed by water forms an ________ with a new carbon-carbon bond. This is an addition reaction because the elements of R'' and H are added across the pi bond. This reaction is used to prepare primary, secondary and tertiary alcohols depending on the number of alkyl groups bonded to the carbonyl carbon of the aldehyde or ketone.

alcohol

LiAlH4 converts acid chlorides and esters to ________

alcohols.

Organometallic reagents (RLi,RMgX,R2CuLi) open epoxide rings to form______

alcohols.

Reduction of aldehydes and ketones to ____________.

alcohols. Aldehydes and ketones are reduced to primary and secondary alcohols, respectively.

Reduction of Aldehydes and Ketones Treating a _________ with a metal hydride reagent results in a primary alcohol. Treating a ___________ with a metal hydride reagent results in a secondary alcohol. catalytic ________________ also reduces aldehydes and ketones to primary and secondary alcohols.

aldehyde, ketone,catalytic

DIBAL or LiALH[OC(CH3)3]3 converts acid chlorides and esters to_______________. These are milder reducing agents while LiAlH4 are strong reducing agents.

aldehydes

siethyl ether is typically removed with a ______ salt such as tetrabutylammoniumfluoride.

fluoride

Reaction of R2CuLi with acid chlorides: Organocuperates react with acid chlorides to afford________. Acid chlorides have the best leaving group and Organocuperates are less reactive than Grignard and Organolithium,

ketones

Carbonyl compounds with leaving groups react with nucleophiles to form substitution products by the two- step process: Nucleophilic attack followed by the loss of the ________________.

leaving group

aldehydes are (more/less) reactive than ketones towards nucleophilic attacks for both steric and electronic reasons?

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