Are Alkyne Reductions Chemo-, Regio-, and Stereoselective Enough To Provide Pure (Z)-Olefins in Polyfunctionalized Bioactive Molecules?

Application to key polyfunctionalyzed precursors in a multistep synthesis thus required high chemo-, regio-, and stereoselective conditions. Depending on the substrate, the choice of the reduction conditions may be crucial for a successful result. The whole argument is organized in three sections. The first section includes an overview of the reducing methods described till now on monoalkynes. Mechanistic information was given except when the mechanism remains unclear. Effectively, their reduction may provide useful vinylsilane precursors while their absence of reactivity is an elegant means to temporarily mask a terminal alkyne, with the latter being an important key intermediate in organic synthesis. The hydroboration-protonolysis sequence affords (Z)-alkenes with good to excellent stereoselectivities and yields depending on the hydroborating reagent and reaction conditions.