Selective Reduction Of Carbonyl Compounds By Potassium Of Octahydrotriborate(KB₃H₈)

The hydroboration reaction,as one of the important organic reactions,refers to the addition of B-H bond in borane to unsaturated double or triple bonds such as C=O,C=C,C?C,etc.to form an organic boron compounds.Once this type of reaction is proposed,it is widely concerned by researchers because it does not rearrange,it is cis addition,and when it is added to asymmetric olefins,it conforms to the anti-Markov Nikov rule,and then it becomes one of the research hotspots.Reduction of carbonyl compounds to corresponding alcohols is also one of the important types of organic reactions in chemical synthesis and has a wide range of applications.Most boranes or their derivatives are good reducing agents and are commonly used to reduce carbonyl compounds,such as ammonia borane and its derivatives,sodium borohydride,lithium borohydride,and so on.Among them,potassium octahydrotriborate(KB₃H₈)has been recently applied to hydrogen storage materials and solid ionic conductors due to its superior properties,but it has rarely been reported as reducing agent.We design and study the reduction of aldehydes and ketones with different functional groups in both water and organic solvents,using KB₃H₈as the reducing agent.Also,the yield,product structure,and selectivity of the reactions were discussed.The experimental results show that KB₃H₈is a mild and efficient reducing agent with strong chemical selectivity.It can reduce the carbonyl groups in aldehydes and ketones in both the aqueous and organic phases without reducing other functional groups.In addition,in the presence of both aromatic aldehydes and ketones,this reagent which shows extremely strong selectivity for aldehyde carbonyl groups,can selectively reduce aldehyde carbonyl groups without reducing keto carbonyl groups.The reduction products were characterized by ¹HNMR,¹³CNMR and crystal structure.