Solid State Organic Reactions

Selective photochemical and ground state organic reactions in the solid state are described. Most reactions are carried out in an inclusion crystal prepared by complexation of a prochiral reactant and an optically active host compound. In the first part of this Account, some optically active host compounds, and preparation of the inclusion crystals are reported. In the second part, some enantioselective Photoreactions of prochiral guest compounds in an inclusion crystal with an optically active host are introduced. In most cases, very efficient enantioselective photoreaction occurred. Some α-oxoamide molecules form chiral crystals without using any chiral source which upon photoirradiation give optically active β-lactams of high optical purities. Some ground state organic reactions also occur in the solid state efficiently and enantioselectively. For example, secondary alcohols form a pair through hydrogen bond formation in their own crystal and treatment of the crystal with TsOH gives the ether very efficiently. The solid state etherification also occurs stereoselectively. In many cases, solid state reactions proceed much faster than the solution reaction, probably because the solid state reaction is a very high concentration reaction. 1. Introduction 2. Host Compounds 3. Preparation of Host-Guest Inclusion Crystals 4. Photoreactions in the Solid State 4.1. Photocyclization of α-Oxoamides 4.2. Photoreaction of Cycloalkenones 4.3. Photodimerization of Coumarin 4.4. Photocyclization of Acrylamides 5. Solid State Organic Reactions 5.1. Benzylic Acid and Pinacol Rearrangement 5.2. Baeyer-Villiger Oxidation 5.3. Reduction 5.4. Grignard, Reformatsky, and Luche Reactions 5.5. Coupling Reactions 5.6. Wittig Reaction 5.7. Aldol Condensation 5.8. Dehydration, Rearrangement, Chlorination, and Etherification of Alcohols 6. Conclusion