DCC (dicyclohexyl carbodiimide)
Dicyclohexyl carbodiimide (DCC) is a reagent used for the synthesis of amides from amines and carboxylic acids. It is essentially a reagent for dehydration (removes water).
DIBAL (diisobutylaluminum hydride)
Di-isobutyl aluminum hydride (DIBAL) is a strong, bulky reducing agent. It is most useful for the partial reduction of esters to aldehydes. It will also reduce other carbonyl compounds such as amides, aldehydes, ketones, and nitriles.
H2CrO4
Chromic acid is a strong acid and an oxidant. It will oxidize secondary alcohols to ketones and primary alcohols to carboxylic acids. It is sometimes generated by using K2Cr2O7 in the presence of a strong acid.
H2O2
Hydrogen peroxide (H2O2) is the preferred oxidant in the hydroboration reaction, resulting in the formation of alcohols. Furthermore, it will oxidize aldehydes to carboxylic acids. This is seen in its use for the oxidative workup in ozonolysis.
H2SO4
Sulfuric acid is a strong acid. It is particularly useful as an acid for elimination reactions, since the conjugate base is a very poor nucleophile. It is used in many other reactions simply as a strong acid.
HIO4
Periodic acid is an oxidant that is useful for the cleavage of 1,2 diols (vicinal diols) into aldehydes or ketones.
KMnO4
Potassium permanganate is a very strong oxidizing agent. It will oxidize primary alcohols and aldehydes to carboxylic acids, secondary alcohols to ketones, form diols from alkenes, and oxidatively cleave carbon-carbon multiple bonds.
KOC(CH3)3
Potassium tert-butoxide is a strong, sterically hindered base. It is the prototypical "bulky base", useful for forming less substituted (Hoffmann) alkenes in elimination reactions.
LDA (lithium diisopropylamide)
Lithium di-isopropylamide (LDA) is a strong, bulky, non-nucleophilic base. It is the reagent of choice for selectively removing a proton from the least hindered carbon next to a ketone. It can also be used to form the Hofmann product in E2 reactions.
LiAlH4
Lithium aluminum hydride is a very strong reducing agent. It will reduce aldehydes, ketones, esters, and carboxylic acids to alcohols, and amides and nitriles to amines. It will also open epoxides.
Lindlar Catalyst
Lindlar's catalyst is a poisoned palladium metal catalyst that performs partial hydrogenation of alkynes in the presence of hydrogen gas. It always gives the cis-alkene, in contrast to Na/NH3, which gives the trans.
mCPBA (m-chloroperoxybenzoic acid)
meta-chloroperoxybenzoic acid (m-CPBA) is an oxidizing agent. One of its main uses is in the formation of epoxides from alkenes. It will also oxidize ketones to form esters, a reaction known as the Baeyer-Villiger reaction.
Me2S
Dimethyl sulfide is used in the "reductive workup" for ozonolysis, especially when one wants to obtain aldehydes from alkenes. It reduces the ozonide that is formed, leading to formation of dimethyl silfoxide (DMSO)
NaBH4
Sodium borohydride is a reagent for the reduction of ketones and aldehydes, it will also reduce acid halides. It is also used in the oxymercuration reaction to replace mercury with H.
NaCNBH3
Sodium cyanoborohydride is a reducing agent. It is generally used for reductive amination - the reduction of imines to amines. Its common to perform this reaction under slightly acidic conditions.
NaIO4
Sodium periodate is a strong oxidant. It will cleave 1,2 diols (vicinal diols) to give aldehydes and ketones.
O3 (ozone)
Ozone will cleave alkenes and alkynes to give carbonyl compounds. This is called oxidative cleavage. The products formed can be dependent on the type of workup used. Reductive workup preserves aldehydes, whereas oxidative workup will oxidize any aldehydes
OsO4
Osmium tetroxide is a reagent for the formation of 1,2-diols (vicinal diols) from alkenes. The selectivity for this reaction is always syn.
PCC (pyridinium chlorochromate)
Pyridinium chlorochromate (PCC) is reagent for the oxidation of primary alcohols to aldehydes and secondary alcohols to ketones. It is much milder than reactants such as H2CrO4 and KmnO4, which will oxidize primary alcohols to carboxylic acids.
Potassium phthalimide
Sodium (or potassium) pthalimide is a nitrogen-containing nucleophile used in the Gabriel synthesis. Potassium pthalimide reacts with alkyl halides to form a C-N bond, which is then hydrolyzed by treatment with hydrazine (NH2NH2) to give a primary amine.
PPh3
PPh3 is used for the formation of ylides in the Wittig reaction. It can also be used for reductive workup in the ozonolysis of alkenes.
Pyridine
Pyridine is a mild base. Since it bears no charges it is especially soluble in organic solvents. It is often used in reactions that generate HCl and other strong acids - think of it like a sponge for strong acid.
Ra-Ni (Rayney nickle)
Rayney nickle is a reagent for the reduction (hydrogenation) of double bonds. It sees the most use as a reagent for the replacement of sulfur by hydrogen.
Ag2O (silver oxide)
Silver oxide is used in the Tollens reaction to oxidize aldehydes to carboxylic acids. This is the basis of a test for the presence of aldehydes, since a mirror of metallic silver will be deposited on the flask. It is also commonly used as a base for the
TMSCI
TMSCl is a protecting group for alcohols. When added to alcohols, it forms a silyl ether, which is inert to most reagents except for fluoride ion and acid. Note that the reagent can be written two ways (CH3)3SiCl and TMSCl.
TsCl (toluenesulfonyl chloride)
Tosyl chloride TsCl will convert alcohols to sulfonates, which are excellent leaving groups in elimination and substitution reactions.