Modern Alkyne Chemistry

Catalytic and Atom-Economic Transformations

Barry M. Trost, Chao-Jun Li, Barry M. Trost, Chao-Jun Li

• Publisher: Wiley-VCH
• Year: 2014
• Print ISBN: 9783527335053
• eBook ISBN: 9783527677917
• Edition: 1
• Topic: Physical Sciences
• Subtopic: Physical & Theoretical Chemistry

A comprehensive and up-to-date overview of alkyne chemistry, taking into account the progress made over the last two decades. The experienced editors are renowned world leaders in the field, while the list of contributors reads like a "Who's Who" of synthetic organic chemistry.
The result is a valuable reference not only for organic chemists at universities and in the chemical industry, but also for biologists and material scientists involved in the modern synthesis of organic compounds and materials.

1
Introduction

Chao-Jun Li and Barry M. Trost

1.1 History of Alkynes

Alkyne is one of the fundamental functional groups that established the foundation of organic chemistry [1]. The smallest member of this family, acetylene, was first discovered in 1836 by Edmund Davy [2]. It was rediscovered and named “acetylene” by Marcellin Berthelot in 1860 by passing vapors of organic compounds through a red-hot tube or sparking electricity through a mixture of cyanogen and hydrogen gas. Acetylene is a moderately common chemical in the universe [3], often in the atmosphere of gas giants. In 1862, Friedrich Wöhler discovered the generation of acetylene from the hydrolysis of calcium carbide (Equation 1.1). Acetylene produced by this reaction was the main source of organic chemicals in the coal-based chemical industry era. When petroleum replaced coal as the chief source of carbon in the 1950s, partial combustion of methane (Equation 1.2) or formation as a side product of hydrocarbon cracking became the prevalent industrial manufacturing processes for acetylene. The next member of the family, propyne, is also mainly prepared by the thermal cracking of hydrocarbons. The first naturally occurring acetylic compound, dehydromatricaria ester (1), was isolated in 1826 [4] from an Artemisia species. Well over 1000 alkyne-containing natural products have been isolated since then, among which many are polyyne-containing natural products isolated from plants, fungi, bacteria, marine sponges, and corals [5].

1.1

1.2

The higher members of alkynes are generally derived from the smaller homologs via alkyne homologation processes of the terminal alkynes (see Equation 1.8, below), while some alkynes are generated through elimination reactions with organic halides under basic conditions (Equation 1.3) [1]. A search in Sci Finder shows that >70 000 terminal alkynes and >10 000 internal alkynes are now commercially available from various sources.

1.3

1.2 Structure and Properties of Alkynes

Alkynes contain a tripe bond, composed of a σ-covalent bond formed from two sp-hybridized carbons and two π-bonds resulted from the overlapping of two orthogonal unhybridized p-orbitals on each carbon (2) [1]. Consequently, alkynes are generally rod-like. Cyclic alkynes are less common with benzyne as an important reactive intermediate in organic chemistry [6]. Acetylene is linear and intrinsically unstable under pressure due to its high compressibility as well as its propensity to undergo exothermic self addition reactions. Consequently, acetylene itself can explode violently at high pressure and the safe limit for acetylene is 103 kPa. Thus, acetylene is generally shipped in acetone or dimethyl formamide (DMF) solutions or contained in a gas cylinder with porous filling [7]. Acetylene has been used as a burning fuel and for illumination purposes in the late nineteenth century and early twentieth century [8]. In modern times, alkynes have found a wide range of applications ranging from organic electronic materials, metal-organic frame works (MOF), pharmaceutical agents, and others [9]. The linearity of the alkyne creates strain when an alkyne is part of a ring [10]. In spite of this fact, cyclopentyne, cyclohexyne, and cycloheptyne can be generated at least fleetingly, their existence being confirmed by in situ trapping, notably by 1,3-dipolar cycloadditions [11]. Cyclooctyne is still highly strained but has sufficient stability to be isolated and used in click chemistry to study biological processes [12].

1.3 Classical Reactions of Alkynes

The higher degree of unsaturation of alkynes compared to alkenes increases their reactivity toward addition to both alkenes and alkynes. In particular, virtually all additions of HX and RX to alkynes are exothermic. Consequently, these stoichiometric addition reactions have been the basis of most reactions in the classical alkyne chemistry (Equation 1.4) [1]. These classical alkyne addition reactions include the additions of hydrogen, halogens, water, hydrogen halides, halohydrins, hydroborations, and others. With a stoichiometric ...

Table of contents

• Cover
• Related Titles
• Title Page
• Copyright
• List of Contributors
• Preface
• Chapter 1: Introduction
• Part I: Catalytic Isomerization of Alkynes
• Part II: Catalytic Cycloaddition Reactions
• Part III: Catalytic Nucleophilic Additions and Substitutions
• Part IV: Other Reactions
• Index
• End User License Agreement