Recent advances in the syntheses, transformations and applications of 1,1-dihalocyclopropanes.

gem-Dihalocyclopropanes have wide-spread applications in organic synthesis due to their versatile chemistry. They can serve as substrates for a large range of useful materials such as natural products, alkaloids, cyclopropanes, heterocycles, aromatic ring systems etc. Normally the dihalocyclopropanes are prepared by the addition of dihalocarbene to alkene, but due to the great synthetic efficacy of gem-dihalocyclopropanes a number of methods have been developed for their synthesis. Generally gem-dihalocyclopropanes exist as strained cyclic systems with astonishing kinetic stability. They are capable of undergoing transformations leading to a variety of products which have potential applications in various synthetic organic chemistry fields.

Recent developments and applications of the Cadiot-Chodkiewicz reaction.

The classical heterocoupling of a 1-haloalkyne with a terminal alkyne catalyzed by copper salts in the presence of a base for the synthesis of unsymmetrical diynes is termed the Cadiot-Chodkiewicz coupling reaction. The diynes are of great importance due to their biological, optical and electronic properties. A number of modifications have been developed recently to improve the efficiency of Cadiot-Chodkiewicz coupling reactions in terms of selectivity and yield. This is the first review on the Cadiot-Chodkiewicz cross-coupling reaction which highlights the modern approaches and protocols developed for the synthesis and applications of unsymmetrical 1,3-diynes.