Double Hydride Transfer Enabled Substitution of All Hydrogens at α,β-Positions of Cyclic Amines: Access to
Ryosuke Yamagishi1, Masahiro Anada2,3, Shunsuke Sueki2,3
1Department of Applied Chemistry, Graduate School of Engineering, Tokyo University of Agriculture and Technology, 2-24-16 Nakacho Koganei, Tokyo 184-8588, Japan.
Abstract:
A one-shot substitution of all hydrogens at the α,β-positions of saturated cyclic amines was achieved. The key feature of this reaction is the sequential involvement of intra- and intermolecular redox processes. When N,O-acetals obtained through an internal redox process were treated with a catalytic amount of Zn(OTf)2 and an excess amount of benzylidene barbiturates, three key transformations involving intermolecular redox process occurred successively to afford α,β-unsaturated lactams in moderate to good chemical yields.
Related Concept Videos
01:20Amides to Amines: LiAlH4 Reduction
Amide reduction requires two equivalents of the reducing agent, acting as a source of hydride ions. As shown in the figure, the reaction is initiated with a nucleophilic attack by the hydride ion at the carbonyl carbon to form a tetrahedral intermediate.
01:07Acid Halides to Amides: Aminolysis
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
00:55Nitriles to Amines: LiAlH4 Reduction
As shown below, the mechanism involves three steps. Firstly, the hydride ion acting as a nucleophile attacks the nitrile carbon to form an anion. In the second step, a second equivalent of the hydride ion attacks the anion to...
00:51Base-Promoted α-Halogenation of Aldehydes and Ketones
01:10α-Alkylation of Ketones via Enolate Ions
01:19Amines to Amides: Acylation of Amines
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary...