金屬有機(jī)化學(xué)ppt課件(參考版)
2025-05-15 03:31本頁(yè)面
【正文】 ? Noyori發(fā)現(xiàn)了 BINAP－ Ru（ II）手性配體，反應(yīng)收率高、對(duì)應(yīng)選擇性好，催化劑易于回收 The Nobel Prize in Chemistry 2022 for their work on chirally catalysed hydrogenation reactions William S. Knowles Ryoji Noyori St. Louis, MO, USA Nagoya University, Chikusa, Nagoya, Japan 1938 for his work on chirally catalysed oxidation reactions K. Barry Sharpless 1941 The Scripps Research Institute La Jolla, CA, USA 1917 常見(jiàn)的手性配體 O OP P h2P P h2P h2PP P h2P P h2P P h2P h2P P P h2P P h2P P h2P P h2P P h2PPM eM eM eM eP hP hC H E t3P P h2C H E t3P P h2FeRuOOOOPPA r2A r2D I O P ( )ME N O (R , R ) D PC P(S , S) C H I R AP H O SN O R PH O SR B I N AP R B I PH EM PR u(R ) BIN AP(S , S) F erroPH O S不對(duì)稱催化氫化的應(yīng)用實(shí)例 R u ( R ) B IN A P不對(duì)稱催化氫化的應(yīng)用實(shí)例 O H O HO HO HN E t2 N E t2O H(R ) 98 %e eR u(s)BI N AP(S) 98 %e eR u(s)BI N APR u(s)BI N AP手性氨基酸 L?Dopa的合成 催化偶聯(lián)反應(yīng) the most mon transition metal catalyst is palladium, as either palladium(0) or palladium(II) the latter gets reduced in situ to palladium(0) anyway Coupling at an Alkenic Hydrogen Site the Heck Reaction Coupling at an Alkenic Hydrogen Site the Heck Reaction Crosscoupling reactions involving Organometallics R1 X +R2M → R1R2 + M X anolithiums, magnesiums， anozincs，anotins， anoboron anolithiums are far too reactive, magnesiums work, but due to a high reactivity they can undergo scrambling of the anometallic moiety to the other coupling partner giving undesired homocoupled products, that are very often difficult to separate from the desired crosscoupled product in any case coupling does not work well and gives poor yields additionally the Grignard reagent does not tolerate the presence of functional groups such as carbonyl, ester and nitril. Crosscoupling of aryl zinc reagents to aryl halides : Negishi Reaction zinc reagents are easily prepared from the corresponding lithium or magnesium reagent and have a lower reactivity, high tolerance to certain functional groups such as carbonyl, ester and nitrile, and a lower tendency towards homocoupling but nevertheless in some cases homocoupling occurs in a few percent sufficiently small to facilitate purification so overall offering much improved results however, zinc reagents are still moisture sensitive which is a practical disadvantage particularly on a large industrial scale. the low degree of homocoupling and the low degree of disproportionation (the loss of the leaving group for H) makes aryl zinc reagents very useful in crosscoupling reactions one particular strength of the aryl zinccouplings is the high degree of selectivity between iodo and bromo leaving groups One area of coupling reactions of ano zincs, seemingly not matched by any other metal is that of alkynyl zinc couplings to aryl halides – such a coupling is obviously useful for the introduction of alkynyl units – but more impor
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