Transition metal-catalyzed cycloaddition reactions

Transition-metal-catalyzed cycloaddition reactions provide a new synthetic method for the construction of a numerous types of ring systems, which are... 

Transition metal-catalyzed cycloaddition reactions of alkynes in syntheses of furans 88CRV1081. 

Cyclopropene, methylenecyclopropane and their derivatives have proved to be valuable reagents in transition metal-catalyzed cycloaddition reactions. Small and medium carbocycles can be prepared by this method. The chemoselectivity observed in some of these reactions is quite remarkable. In addition, high degree of regio- and stereoselectivity is obtained in most cases. In particular the new [3+2] cycloaddition described here and which involves methylenecyclopropane and its derivatives as trimethylenemethane synthones, shows great synthetic promise as a method for constructing fivemembered rings. 

TRANSITION-METAL-CATALYZED CYCLOADDITION REACTIONS OF BICYCLO[2.2.1]HEPTA-2,5-DIENES (NORBORNADIENES)... 

Metallacycles are also featured in Chapters 2 and 3 of this volume. Cobalt- and nickel-based metallacycles are key cataljrtic intermediates in Transition-Metal-Catalyzed Cycloaddition Reactions of Bicy-clo[2.2.1]heptadienes by Professor Mark Lautens and Dr. William Tam of the University of Toronto (Chapter 2). The high sttain energy of norbomadiene makes possible many of the interesting processes covered in this informative chapter. It is followed by a comprehensive review of the State of the Art in Selective Hetero- and Carbocyclic Synthesis Mediated by Cyclometallated Complexes ... 

In this section the transition metal catalyzed cycloaddition reactions of polyunsaturated aza-macrocycles are considered for the creation of condensed polycyclic structures. The effect of structural construction of the polialkyne- and enediyne-aza-macrocycles were studied with respect to their chain length, effect of substituents in certain positions, and the nature of unsaturation in the [2- -2- -2] cycloaddition reaction. 

---