The Application Of Single Electron Transfer Of Allyl Samarium And The Barbier Reactions Promoted By Praseodymium

Rare earth metal reagents are one of the hot areas in organic synthesis in recentyears. The development of rare earth metal-mediated reactions with high selectivity isvital for better understanding the nature of them.The thesis consists of the following two sections:1. The reaction of allylsamarium reagent with aldehydes and ketones in thepresence of diphenyl phosphite affords terminal olefins and conjugated olefins.Compared with similar allyl Grignard reagent, it is not easy to coupling forallylsamarium bromide. The role of a single electron transfer reagent for allylsamariumbromide has been reported by our group for the first time. Based on our previous work,we use simple carbonyl compounds as substrate, then add another additive to promoteits single electron transfer to give the target products. At last, we found diethylphosphite can play a facilitating role. These systems have significant advantages：(1)Substrates of aldehydes are cheap and easy to get;(2) The reaction can realize one-potsynthesis of olefin;(3) The reaction is further validation of a single electron transfer ofallylsamarium. We proposed and verifided the possible mechanism for this reaction.2. The second part is about praseodymium-mediated Barbier reaction of ketones.As one of the major rare earth metals, research of praseodymium is quite limited. So,Barbier reaction of ketones and haloalkanes promoted by praseodymium issystematically studied. The reaction conditions are mild and the corresponding alcoholsare achieved in high yields without any additives.