Direct Addition Of Grignard Reagents To Cyclic ?-diketones Promoted By I-PrMgCl

The carbon-carbon bond formation reaction is a fundamental organic reaction,which is always the hot spot of organic chemistry study.In chemical synthesis,the addition reaction of Grignard reagent and carbonyls is typically used to the carbon-carbon bond formation reaction.In this work,we used isopropyl magnesium chloride(i-PrMgCl)to promote the addition of Bromide Grignard reagents to cyclic ?-diketones.The cyclic 3-substituted eones can be obtained due to subsequent intramolecular dehydration,which is the key structure of sesquiterpene(Laurene and Cuparenone)that widely used in the field of medicine,spice,cosmetic and food.Besides that,the derivatives of cyclic 3-substituted enones can cure many inflammatory conditions such as bronchiectasis,asthma,autoimmune disease,etc.Generally speaking,we can get cyclic 3-substituted enones by a cascade two-step way,which has always given low yield.In this work,we found a readily available isopropyl magnesium chloride can achieve the reaction conveniently by direct one step,and most products can be obtained in good yield with no addition of toxic reagents and other additives.