Proceeding through a concerted, aromatic transition state, the Diels-Alder [4π+2π] cycloaddition uses heat to form a cyclohexene derivative from an electron rich (s-cis) diene and an electron poor dienophile (referred to as the normal electron-demand Diels-Alder reaction). Benefits include the conservation of the starting dienophile’s stereochemistry and the high regioselectivity...

The formation of a C-C single bond between the α-position of a conjugated carbonyl compound and a carbon electrophile in the presence of a nucleophilic Lewis Base catalyst is known as the Baylis-Hillman reaction. A Michael addition of the catalyst occurs at the β-position of the conjugated carbonyl compound, forming...

The Cannizzaro reaction utilizes a strong base and two aldehydes with no α-hydrogens: one is reduced to the corresponding 1° alcohol, while the other is oxidized to a carboxylic acid in a maximum yield of 50% each. Although a variety of mechanisms have been proposed, the generally accepted mechanism involves...

The Ireland-Claisen (also known as the ester enolate Claisen rearrangement) uses lithium diisopropylamide (LDA), trimethylsilyl chloride (TMSCI), sodium hydroxide, and water to convert an allyl ester to a γ, δ-unsaturated carboxylic acid. The α-hydrogen of the allyl ester is deprotonated by LDA, creating an enolate, which attacks TMSCl, releasing LiCl...

The Gabriel synthesis uses phthalimide, a base, an alkyl halide, and hydrazine to make a 1° amine in a two-step process. First phthalimide is alkylated with an alkyl halide via an SN2 reaction, forming N-alkylphthalimide. Next, hydrazine attacks a carbonyl group of N-alkylphthalimide, resulting in the ring opening, followed by...

Adding a keto group to an aromatic or aliphatic substrate using an acyl halide or anhydride in the presence of a Lewis acid catalyst is called the Friedel-Crafts acylation. The reactive electrophile in this aromatic substitution is either an acylium ion or an acyl chloride-Lewis acid complex. [1] Benzene and...