| Qualified with such advantages that non-toxic,cheap,easily removed during the final workup,and such properties that high chemical regional selectivity and good stability,Organoanganese reagents match the values of efficient,atom-economic and eco-friendly chemistry,having great application value and application potential in organic synthesis.Common coupling reactions including the homocoupling and cross-coupling reactions must be carried out in the presence of the transion-metal catalysts.Taking advantage of the hige chemical regional selectivity,catalyst-free coupling reactions can be done by means of the organoanganese reagents. This paper is about the study on the catalytic-free coupling reactions of organomanganese reagents.Organomanganese reagents could be prepared via transmetalation from the corresponding organolithium or organomagnesium reagents.Various of functionalized organomanganeses would be easily prepared since the starting functionalized organolithium and organomagnesium reagents are not always trival to prepare.Homocoupling reactions of organomanganese reagents yield high productions by treatment with the oxidant of3,3’,5,5’-tetra-tert-butyldiphenoquinone obtained from 2,6-Di-tert-butylphenol.All the homocoupling yields are all over 50% and highest of which is 85.1%,illustrating the excellent result of the transition-metal-free homocoupling of organomanganese reagents.Allylic compounds,leading to SN2 and SN2’ substitution reactions meets the research focus that high regional selectivity and high eiffient of organomanganese reagents in the cross coupling reactions,are chosen to be the reaction substrate.During the selection of nucleophilic reagents, cinnamylchloride reacted with phenyl Grignard reagent and phenyl Grignard reagent mixed with 10mol% 的 MnCl2·2LiCl respectively.The later reagent resulted in higher yield substitutions and higher ratio α-substitution product,showing the selectivity of organomanganese is prior to that of Grignard reagents.Allylic compounds contains allyl halides and allyl esters,however,allylic esters are much stable than allylic halides.Besides,allylic esters like carbonic ester and organic phosphate are all good good leaving group.So the allylic esters are chosen to be the reaction subatrate. When phenyl organic manganese reagents reacted with cinnamylchloride,cinnamyl acetate and phosphoricacid cinnamyl ester, phosphoric acid cinnamyl ester led to the highest yield 77%. The subsequent research result showed that reaction between organomanganese reagents and cinnamyl acetates is another type reaction and are still under study by other people in the laboratory.At last, the phosphoric acid cinnamyl esters were chosen to be reaction substrate.The cross coupling reactions between various functionalized organomanganese reagents and phosphoric acid cinnamyl esters all gave birth to high yield substitution product and high regional selectivity,the ratio of α- substitution product are all over 99:1.The transition-metal-free catalyzed homocoupling and cross coupling reactions of organomanganese compounds could be underway with high yield and high regional selectivity.In addition of that,the metal manganese characterized with the qualities of cheap,eco-friendly,and easy removed.All of these endue organomanganese reagents with special meaning in organochemistry. |
