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A simplified monomer-addition model with a first-order activation step is developed to describe the dynamics of growth of silica particles from alkoxides. In the fimit of slow hydrolysis, we obtain expressions for the evolution of the particle mass and particle polydispersity, as well as an expression for the particle size as a function of the hydrolysis rate constant, the polymerization rate c...

A process for preparation of amides from unactivated esters and amines has been developed using a catalytic system comprised of group (IV) metal alkoxides in conjunction with additives including 1-hydroxy-7-azabenzotriazole (HOAt). In general, ester-amide exchange proceeds using a variety of structurally diverse esters and amines without azeotropic reflux to remove the alcohol byproduct. Initia...

Allenes can be synthesized via the direct SN2' addition of hydride to propargylic alcohols. Previous examples of this approach, however, have involved harsh reaction conditions and have suffered from incomplete transfer of central chirality to axial chirality. Here we show that Cp2Zr(H)Cl can react with the zinc or magnesium alkoxides of propargylic alcohols to generate allenes in good yield an...

Reaction of readily available N-benzylbenzamide (I) with a slight excess of BuLi produces a deep blue dianion. Under suitable conditions (THF, -40*(2), 1 may be used as a stoichiometric reagent to titrate n-BuLl, s-BuLi, and t-BuLi with good precision. Less reactive alkyllithiums (MeLi and MeLi, LiBr), aryllithiums, and LDA may be titrated at higher temperatures ( 20 to 0°C). Titres are compara...