Transition metal catalysed formation of Csp2-S bond through cross-coupling reaction stands important and powerful tools in synthetic organic chemistry. The reaction constitutes an important strategy for the synthesis of thioethers that possess diverse biological activities in medicine and agriculture. Nonetheless, maintaining reaction temperature during Csp2-S crosscoupling reaction decides fate of desired product along with possibility of by-product and disulfides. The economy of process, safety and environmental issue demands thioether synthesis at mild condition and room temperature. Only very few reactions were successful under mild condition using Pd, Cu, Ni, NiÀ Ir and Ir catalyst. The current prospective summarizes the best protocols used for efficient Csp2-S cross-coupling reactions by transition metal catalyst under mild condition.

In this work, an oxo-bridged bimetallic CuMoO 4 catalyst for Csp 2 À Se cross-coupling of diaryldiselenides with aryl-halides is reported. The current discovery is noteworthy, as the catalyst is eco-friendly, easily accessible, air-stable, and recyclable. The methodology exhibits broad substrate scope and the catalytic system tolerates common functional groups.The protocol uses aryl iodide and bromides as electrophile instead of boronic acids. This is the first example of using an oxo-bridged copper based bimetallic catalyst for Csp 2 À Se cross-coupling reactions in water. CÀ Cl bond remains intact during reaction.

Formation of carbon-selenium bond by Csp 2 -Se cross-coupling using diaryldiselenides and arylhalides are very few in literature. Herein we report CuSeO 3 .2H 2 O as an efficient catalyst for direct Csp 2 -Se cross-coupling of diaryldiselenides with aryl iodides, bromides and aryl boronic acids. The reaction is performed at low temperature (70 °C) in tert-butanol solvent in absence of ligand. Arylboronic acids are more reactive than aryliodides and bromides.