A tetranuclear magnesium hydride cluster with a four-coordinate hydride in near square-planar geometry.

A tetranuclear magnesium hydride complex based on the β-oxo-δ-diiminate (BODDI) ligand was isolated. In the solid state, the complex features three bridging μ-hydrides and one unprecedented four-coordinate hydride in a nearly square-planar coordination environment. In the solid state, two different coordination polymers are observed depending on whether the axial or equatorial oxygen lone pairs of 1,4-dioxane are engaged in bonding to magnesium.

-Selective phosphine promoted 1,4-reduction of ynoates and propynoic amides in the presence of water.

Phosphine-mediated reductions of substituted propynoic esters and amides in the presence of water yield the partially reduced α,β-unsaturated esters and amides with high Z-selectivity. The competitive in situ Z to E-isomerization of the product in some cases lowers the Z to E ratios of the isolated α,β-unsaturated carbonyl products. Reaction time and the amounts of phosphine and water in the reaction mixture are the key experimental factors which control the selectivity by preventing or reducing the rates of Z- to E-product isomerization.

trans-Hydroboration vs. 1,2-reduction: divergent reactivity of ynones and ynoates in Lewis-base-catalyzed reactions with pinacolborane.

Ynones and ynoates react with pinacolborane in a divergent manner in the presence of nucleophilic phosphine catalysts. Ynones are transformed to the corresponding propargyl alcohols in good yields with high regio- and chemoselectivity. Ynoates undergo highly regio- and stereoselective trans-hydroboration to produce E-vinylboronates.