ABSTRACT
1,4-Butanediol is able to deliver two equivalents of H(2) in hydrogen-transfer reactions to ketones, imines, and alkenes. Unlike simple alcohols, which establish equilibrium in the reduction of ketones, 1,4-butanediol acts essentially irreversibly owing to the formation of butyrolactone, which acts as a thermodynamic sink. It is therefore not necessary to use 1,4-butanediol in great excess in order to achieve reduction reactions. In addition, allylic alcohols are reduced to saturated alcohols through an isomerization/reduction sequence using a ruthenium catalyst with 1,4-butanediol as the reducing agent. Imines and alkenes are also reduced under similar conditions.
Subject(s)
Butylene Glycols/chemistry , Reducing Agents/chemistry , Alkenes/chemistry , Hydrogenation , Imines/chemistry , Isomerism , Lactones/chemistry , Propanols/chemistry , Ruthenium/chemistryABSTRACT
The alkylation of amines by alcohols has been achieved using 0.5 mol % [Ru(p-cymene)Cl(2)](2) with the bidentate phosphines dppf or DPEphos as the catalyst. Primary amines have been converted into secondary amines, and secondary amines into tertiary amines, including the syntheses of Piribedil, Tripelennamine, and Chlorpheniramine. N-Heterocyclization reactions of primary amines are reported, as well as alkylation reactions of primary sulfonamides. Secondary alcohols require more forcing conditions than primary alcohols but are still effective alkylating agents in the presence of this catalyst.
Subject(s)
Amines/chemical synthesis , Sulfonamides/chemical synthesis , Alcohols/chemistry , Alkylation , Amines/chemistry , Catalysis , Cymenes , Organometallic Compounds/chemistry , Sulfonamides/chemistryABSTRACT
1,4-Butanediol has been used as the hydrogen donor in transfer hydrogenation reactions. The equilibrium is driven by the formation of gamma-butyrolactone, and the diol is therefore not required in excess.
