A novel, efficient transition-metal-free and controllable boration/protodeboronation strategy has been developed for the chemoselective conjugate addition and 1,4-reduction of α,β-unsaturated carbonyl compounds. Without any metal-catalyst or base, a series of β-boration products of α,β-unsaturated carbonyl compounds was easily obtained in moderate to excellent yields in a mixed solvent of ethanol and water. The presence of a catalytic amount of Cs₂CO₃ can effectively induce further protodeboronation reaction towards 1,4-reduction products at higher reaction temperature. Therefore, by slightly changing the reaction conditions, the boration or reduction products of α,β-unsaturated carbonyl compounds can be controllably obtained. Mechanistic studies revealed that Cs₂CO₃ played the key role in activating the protodeboronation step. This transition-metal-catalyst-free and product controllable method provides a useful and eco-friendly tool for the highly chemoselective preparation of the β-boration products and 1,4-reduction products of α,β-unsaturated carbonyl compounds.

中文翻译：

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通过可控的硼酸化/原脱硼烷级联途径，无催化剂的化学选择性共轭物的添加和α，β-不饱和羰基化合物的还原

已开发出一种新颖，有效的无过渡金属且可控制的硼酸化/原硼酸脱硼策略，用于化学选择性结合物的添加和α，β-不饱和羰基化合物的1,4-还原。在没有任何金属催化剂或碱的情况下，在乙醇和水的混合溶剂中，很容易以中等至极好的收率获得一系列α，β-不饱和羰基化合物的β-硼酸酯产物。催化量的Cs ₂ CO _3的存在可以在较高的反应温度下有效地引发进一步的原硼酸脱硼反应，生成1,4-还原产物。因此，通过稍微改变反应条件，可控制地获得α，β-不饱和羰基化合物的硼酸化或还原产物。机理研究表明Cs ₂CO ₃在激活原去硼化步骤中起关键作用。这种无过渡金属催化剂且产物可控的方法为高化学选择性制备α，β-不饱和羰基化合物的β-硼酸酯产物和1,4-还原产物提供了有用且环保的工具。