A modular synthesis of the lamellarins: total synthesis of lamellarin G trimethyl ether
Scott T Handy1, Yanan Zhang, Howard Bregman
1Department of Chemistry, State University of New York at Binghamton, Binghamton, New York 13902, USA. shandy@binghamton.edu
Abstract:
A modular synthesis of the lamellarin family of natural products has been developed that is based on the application of three iterative halogenation/cross-coupling reaction sequences. The ability to halogenate the pyrrole core in a regioselective fashion, even in the presence of highly electron-rich aryl substituents, has been established. The compatibility of Suzuki coupling conditions with free alcohols and phenols in the boronic acids has been employed to reduce the number of protection/deprotection steps. Indeed, the presence of a free phenol on boronic acid 3 has been determined to be critical for the successful final coupling in route to lamellarin G trimethyl ether, since protected versions fail to undergo coupling.
Related Concept Videos
Alkylation of β-Diester Enolates: Malonic Ester Synthesis
Sharpless Epoxidation
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
Ethers from Alcohols: Alcohol Dehydration and Williamson Ether Synthesis
Ethers can be prepared from organic compounds by various methods. Some of them are discussed below,
Preparation of Ethers by Alcohol Dehydration
In this method, in the presence of protic acids, alcohol dehydrates to produce alkenes and ethers under different conditions. For example, in the presence of sulphuric acid, dehydration of ethanol at 413 K yields ethoxyethane, whereas it yields ethene at 443 K.
Ethers from Alkenes: Alcohol Addition and Alkoxymercuration-Demercuration
Ethers can also be prepared from alkenes through acid-catalyzed addition of alcohols and alkoxymercuration–demercuration.
Preparation of Ethers by Acid-Catalyzed Addition of Alcohol to Alkenes
The acid-catalyzed addition of alcohol to an alkene involves treating the alkene with an excess of alcohol in the presence of an acid catalyst to form an ether under suitable conditions. The hydrogen will add to the less substituted carbon so that the nucleophile can attack the more substituted...


