The significant increase in applications of Barbier and Barbier-type reactions in (in-) organic synthesis over the past twenty-five years, combined with repeated stimulation on the part of Springer-Verlag (Dr. R. Stumpe) were strong in­ centives for me to write this book. My earliest activities in this field include a modest and first-ever review article (in cooperation with Dr. F. A. Hartog who at that time (1977) did his doctoral research on the Barbier reaction). References to this review article, as mentioned in the Science Citation Index till recently are a good indication for a continued interest in this simple synthetic procedure. The subtitle of this monograph, Related One-Step Processes, may require the following clarification. A synthesis with the aid of an organometallic compound is usually carried out in two steps: 1) the organometallic reagent is prepared from an organo halide and a metal in a solvent, 2) a chosen substrate is added to this reagent. In a Barbier reaction these two steps are combined: a mixture of the organo halide and the substrate is added to a suspension of the metal-in an appropriate solvent.

Inhalt

1 Introduction.- 1.1 Magnesium: A New Metal in Organic Synthesis.- 1.2 The Early History of Organozinc Chemistry.- 1.2.1 The Beginning of Organozinc Chemistry.- 1.2.2 Improvement of the Preparation of Diethylzinc.- 1.2.3 Synthetic Applications of Organozinc Compounds.- 1.2.4 Barbier Reaction: Saytzeff or Frankland Reaction?.- 1.2.5 Zinc in Organic Chemistry.- 1.3 The Early History of Organomagnesium Chemistry.- 1.3.1 Pre-Barbier Period.- 1.3.2 Magnesium in Synthetic, Organic Chemistry.- 1.4 The Barbier Reaction.- 1.5 More Recent Developments in Barbier Chemistry.- 1.6 Contents of the Following Chapters.- 1.7 References.- 2 Synthetic Applications of the Barbier Reaction.- 2.1 Synthetic Procedures: One-Step or Two-Step?.- 2.2 The Replacement of Zinc by Magnesium in the Reformatsky Reaction.- 2.3 Barbier Reactions with Allylic Halides.- 2.3.1 Introduction.- 2.3.2 The Jaworsky Reaction.- 2.3.3 Allylmagnesium Halides.- 2.3.4 More Barbier-Type Reactions with Allylic Halides.- 2.3.5 Allylic Rearrangements.- 2.4 Other Barbier Reactions.- 2.4.1 Introduction.- 2.4.2 Intramolecular Barbier Reactions.- 2.4.3 Reactions with Cyclic Acetals.- 2.4.4 Miscellaneous Barbier Reactions.- 2.4.5 Barbier Reactions with Halides of Various Elements.- 2.5 Conclusion.- 2.6 References.- 3 Barbier-Type Reactions with Other Metals.- 3.1 Introduction.- 3.2 Sodium in One-Step Processes.- 3.3 Lithium in Barbier-Type Reactions.- 3.3.1 Cyclization Reaction; 1968.- 3.3.2 One-Step Alternative to the Grignard Reaction.- 3.3.3 Allylic Mesitoates.- 3.3.4 Cyclization Reactions; 1975.- 3.3.5 Reactions with Nitriles and Nitrosoalkanes.- 3.3.6 Reactions with Sterically Crowded Halides; 1978.- 3.3.7 Ultrasound in Li-Barbier Reactions.- 3.3.8 Other Li-Barbier Reactions with Sterically Hindered Reagents; 1988.- 3.3.9 Li-Barbier Reactions with n-Butyllithium.- 3.4 Zinc in Barbier-Type Reactions.- 3.4.1 Introduction.- 3.4.2 'Saytzeff Reactions' with Propargylic Halides.- 3.4.3 Zn-Barbier Reactions with Perfluoro Haloakanes.- 3.4.4 Other Zn-Barbier Reactions; Solvents, Activating Agents.- 3.4.5 Conclusion.- 3.5 Other Metals in Barbier-Type Reactions.- 3.6 Summary.- 3.7 References.- 4 The Mechanism of the Barbier Reaction.- 4.1 Introduction.- 4.2 Mechanism of the Interaction of Metals with Organo Halides.- 4.2.1 Early Work by Polanyi et al.; 1934.- 4.2.2 'High Temperature Species'; 1967.- 4.2.3 Vapourization of Metals and Codeposition with Reactants.- 4.2.4 Conclusion.- 4.3 Mechanism of the Grignard Reagent Formation Reaction.- 4.3.1 Introduction.- 4.3.2 Studies on Radical Formation.- 4.4 Mechanism of the Barbier Reaction.- 4.4.1 Introduction.- 4.4.2 Radical Formation.- 4.4.3 Conclusion.- 4.5 References.- 5 Experimental Procedures for Barbier Reactions.- 5.1 Introduction.- 5.2 Starting Heterogeneous Reactions with Metals.- 5.2.1 Introduction.- 5.2.2 Anhydrous Reaction Conditions.- 5.3 Reactions with Magnesium.- 5.3.1 Introduction.- 5.3.2 Surface of Metallic Magnesium.- 5.3.3 New Developments in Activation of Magnesium.- 5.3.4 General Conclusion Regarding Magnesium Activation.- 5.4 Reactions with Lithium.- 5.4.1 Introduction.- 5.4.2 Activation of Lithium Metal.- 5.5 Reactions with Zinc.- 5.5.1 Introduction.- 5.5.2 Chemical Activation of Zinc.- 5.5.3 Other Techniques to Activate Zinc.- 5.5.4 General Conclusion Regarding Zinc Activation.- 5.6 References.