Conjugate Hydrocyanationof Dienones Using Potassium Hexacyanoferrate(Ⅱ) As An Eco-friendly Cyanide Source And Synthesis Of Benzils From Chalcones

Organic cyanationis very important in organic synthesis.Because of its special structure of the cyano group, it can convert into many other important groups, such as: carboxylic acids, amines, amidines, tetrazoles, and amides. Many organic compounds could be synthesized from cyanation reactions,such as cyanohydrins, nitriles, α-aminonitriles, α-aminoketones and hydrazinonitriles, α-amino acids and β-amino acids. However, the traditionalcyanide resources are highly toxic substances, such asHCN, metal cyanides and so on. These highly toxic cyanide sourcescould also cause serious environment problems.Therefore,seeking a non-toxic and environmentally friendly cyanide sources has become the common goalsfor researchers. Potassium hexacyanoferrate(II)can give us some hope to achieve this hope. Potassium hexacyanoferrate(II) is a byproduct of coal chemical industry, and often used in food additives.It is a non-toxic substance, and is a safe and green cyanide source.It is known to us that 1,2-diketones are important synthetic building blocks in both organic synthetic chemistry and chemical industry. It has also shown interesting applications in many other areas. However, the synthesis of 1,2-diketones remains a big challenge. Though there are many different method to synthesizethem, they still exist many disadvantages, such as low yields, using hazardous and toxic reagents or catalyst and so on.Therefore, it is necessary to find a new method for 1,2-diketones.This paper is focused onconjugate hydrocyanation of dienones using potassium hexacyanoferrate(II) as an eco-friendly cyanide source and the synthesis of benzils from chalcones.The paper is divided into threechapters.Chapter I:The progressesof cyanide sources in organic cyanationreactions,and the synthetic methods for benzils are reviewed.Chapter II:Regioselective 1,4-conjugate hydrocyanation of dienones using potassium hexacyanoferrate(II) as an eco-friendly cyanide source and benzoyl chloride as a promoter to synthesize a series of β-cyanoenones has developed. The advantages of this method are the use of green cyanide source, simple work-up procrdure and high yield.Chapter III:A novel method for the synthesis of benzils using chalcones as substrates, copper as a mediator, and air as an oxidant is described. This protocol has advantages of mild condition, high yield and simple work-up procedure.