Sarah E. Kelly

3.1 – Alkene Synthesis

In this chapter, the various methods of converting a carbonyl derivative to an alkene are discussed. Particular focus has been given to recently developed methods and their use in the context of natural product synthesis. Formally this volume in the series is devoted to nonstabilized carbanion additions, but this mechanistic definition has not been strictly adhered to in this chapter. The methods are categorized according to the type of alkene synthesized, and the stabilizing group attached to the anion or carbene. In addition, all of the methods discussed involve the addition of a carbon unit to the carbonyl, followed by some type of elimination or cleavage to the alkene. To further narrow the scope of this chapter, the added carbon unit and the original carbonyl carbon must form the units of the alkene, as shown in Scheme 1. Aldehydes, ketones, esters and lactones, and amides and lactams are all featured in these sections, depending on the synthetic method being discussed.

A One Pot Procedure for the Synthesis of α-Hydroxyamides from the Corresponding α-Hydroxyacids

Abstract α-Hydroxyamides are synthesized from the cooresponding α-hydroxyacids by generation of the bis-trimethylsilyl derivative and treating it with oxalyl chloride. Following addition of the appropriate amine, the TMS ether is hydrolyzed in the workup to provide the desired α-hydroxyamide. As summarized in Table I, this reaction has proven to be general and compatible with chiral α-hydroxyacids affording the desired α-hydroxyamides in excellent yield (77–99%).

An efficient synthesis of (S)-2-hexylthiodecanoic acid

Abstract A short synthesis of (S)-2-hexylthiodecanoic acid from racemic 2-hydroxydecanoic acid is described. This material is useful as a sidechain for ACAT inhibitors.

A Novel Synthesis of 3-Amido-5-phenyl-benzazepin-2-one via an Intramolecular Amidoalkylation

Abstract A synthesis of N-(8-Methyl-2-oxo-5-phenyl-2,3-dihydro-1H-benz[b]azepin-3-yl)-benzamide 2 via an intramolecular amidoalkylation is described.