The Cross-coupling Reaction Between Benzylic Halides And Carbamoylsilane Under Catalysis By Palladium Complexes

Amide is widely used in synthesis of organic molecules,polymers, active compounds and the natural products. And asimportant organic material in pharmaceuticals, cosmetics, dyestuff,oil, chemical and electronic industries. Many preparation methodsof amide, such as Heck reaction, Suzuki Miyaura reaction,Sonogashira reaction, formylation, amide carbonylation and metalcatalyst fold nitrogen compound coupling method, etc. Among them,the palladium catalyst ammonia acylation reaction is the mostpromising method, but the drawback is: CO toxic, and under thecondition of high temperature and high pressure operation.Therefore, developing a non-toxic reagent, under atmosphericpressure, simple preparation process, high yield and wideapplication range and has strong practicability method is necessaryThis paper is mainly about two kinds of carbamoylsilanes whichwe have synthesized successfully, and studies treatment of allylichalides with two carbamoylsilanes in the presence of tree palladiumcomplexes. We have tried and chosen the best catalyst, solvent andtemperature of the two kinds of reactions. Under these conditions, wecarry on the experiment that are carbamoylsilanes with allylic undercatalysis by tetrakis(triphenylphosphine)palladium(0), bis(tritert-butylphosphine)palladium(0) and bis(triphenylphosphine)palladium (II). Also, we have investigated the influence of palladium catalyst andthe steric and electronic effects on reaction time and yield.The reaction with benzyl chloride8; o-fluorobenzylchloride9;p-fluorobenzylchloride10; o-chlorobenzylchloride11; m-chlorobenzyl-chloride12; p-chlorobenzylchloride13; o-cyanbenzylchloride14; m-cyanbenzylchloride15; p-cyanbenzylchloride16; o-methylbenzylchlor-ide17; m-methylbenzylchloride18; p-methylbenzylchloride19; p-met-hoxylbenzylchloride20;2,4-dichlorobenzylchloride21;3,4-dichlorobe-nzylchloride22;2,6-dichlorobenzylchloride23; p-nitrylbenzylchloride24; chlorodiphenylmethane25; cinnamylchloride26;1-(chloromethyl)-naphthalene27in the presence of three palladium complexes.Among these reaction2,6-dichlorobenzylchloride23; p-nitrylbenzylch-loride24; chlorodiphenylmethane25not action, other products areN-methyl-N-(methoxymethyl)benzethylamide28;(2-fluoro)-N-methyl-N-(methoxymethyl)benzethylamide29;(4-fluoro)-N-methyl-N-(methox-ymethyl)benethylamide30;(2-chloro)-N-methyl-N-(methoxymethy-l)benzet-hylamide31;(3-chloro)-N-methyl-N-(methoxymethyl)benzeth-ylamide32;(4-chloro)-N-methyl-N-(methoxymethyl)benzethylamide33;(2-cyan)-N-methyl-N-(methoxymethyl)benzethylamide34;(3-cyan)-N-methyl-N-(methoxymethyl)benzethylamide35;(4-cyan)-N-methyl-N-(methoxymethyl)benzethylamide36;(2-methyl)-N-methyl-N-(methoxy-methyl)benzethylamide37;(3-methyl)-N-methyl-N-(methoxymethyl)b-enzethylamide38;(4-methyl)-N-methyl-N-(methoxymethyl)benzethyla-mide39;(4-methoxyl)-N-methyl-N-(methoxymethyl)benzethylamide40;(2,4-dichloro)-N-methyl-N-(methoxymethyl)benzethylamide41;(3,4-di-chloro)-N-methyl-N-(methoxymethyl)benzethylamide42;4-benzethyl-3-butenyl-N-methyl-N-(methoxymethyl)benztertiaryamide46;1-napht- halene-N-methyl-N-(methoxymethyl)benztertiaryamide47. Comparingthree kinds of results of catalysts we know:[(Ph)3P]4Pd (0) canimprove reactivity connected with electron-donating groups on thebenzene ring;[(Ph)3P]2PdCl2(ii) enhances even the reaction of theelectron-withdrawing Group on the benzene ring of reactivity;[(t-Bu)3P]2Pd (0) alone on the reactivity of the benzene ring connectedwith CN’s response. From the experimental results, we will find: whenthe electron-pushing on the benzene ring, reactivity increases; Evenwhen there are electron-withdrawing, the opposite; When on thebenzene ring ortho-substituent is attached, reactivity incresses; Evenwhen there is a substituent, it has little effect on the reaction.Reaction between two substituents on the benzene ring is not asatisfactory situation, and may be affected by the combined effects ofsteric and inductive effect. Although the N-methyl-N-oxymethylcar-bamylsilane and a series of chloride benzyls under the Palladiumcatalyzed coupling reactions can occur, the yield is not very high.N-methyl-N-(2-benzethyl)benzethylcarbamoylsilane reaction withbenzyl chloride8; o-fluorobenzylchloride9; p-fluorobenzylchloride10;o-chlorobenzylchloride11; m-chlorobenzylchloride12; p-chlorobenzyl-chloride13; o-cyanbenzylchloride14; m-cyanbenzylchloride15; p-cya-nbenzylchloride16; o-methylbenzylchloride17; m-methylbenzylchlori-de18; p-methylbenzylchloride19; p-methoxylbenzylchloride20;2,4-di-chlorobenzylchloride21;3,4-dichlorobenzylchloride22;2,6-dichlorob-enzylchloride23; p-nitrylbenzylchloride24; chlorodiphenylmethane25; cinnamylchloride26;1-(chloromethyl)naphthalene27in thepresence of tetrakis(triphenylphosphine)palladium(0). Among thesereaction2,6-dichlorobenzylchloride23; p-nitrylbenzylchloride24; chlorodiphenylmethane25do not act, other products areN-methyl-N-(2-benzethyl)benzethylamide49;(2-fluoro)-N-methyl-N-(2-benzethyl)benzethylamide50;(4-fluoro)-N-methyl-N-(2-benzethyl)ben-zethylamide51;(2-chloro)-N-methyl-N-(2-benzethyl)benzethylamide52;(3-chloro)-N-methyl-N-(2-benzethyl)benzethylamide53;(4-chloro)-N-methyl-N-(2-benzethyl)benzethylamide54;(2-cyan)-N-methyl-N-(2-benzethyl)benzethylamide55;(3-cyan)-N-methyl-N-(2-benzethyl)benz-ethylamide56;(4-cyan)-N-methyl-N-(2-benzethyl)benzethylamide57;(2-methyl)-N-methyl-N-(2-benzethyl)benzethylamide58;(3-methyl)-N-methyl-N-(2-benzethyl)benzethylamide59;(4-methyl)-N-methyl-N-(2-benzethyl)benzethylamide60;(4-methoxyl)-N-methyl-N-(2-benzethyl)benzethylamide61;(2,4-dichloro)-N-methyl-N-(2-benzethyl)benzethyl-amide62;(3,4-dichloro)-N-methyl-N-(2-benzethyl)benzethylamide63;4-benzethyl-3-butenyl-N-methyl-N-(2-benzethyl)benztertiaryamide67;1-naphthalene-N-methyl-N-(2-benzethyl)benztertiaryamide68. Resul-ts of this series of reactions are similar to previous experiments, butthere are some differences: when on the benzene ring connected withelectron withdrawing groups such as halogens, cyanogen radicalshave a longer reaction time and yield decreased; but if the halogen,cyano, methoxy-methyl and other electron-withdrawing attached tothe benzene ring, the yield is very high. When on the benzeneconnected with electron donating groups such as methyl, cinnamylradicals, and naphthalene can substantially increase the reactivity ofnot only shorten the reaction time, but the product yields are high;when there are two substituents on the benzene ring, reactivity isrestraint, even not react.In a word, through this research,17secondary amide comp- ounds and17tertiary amide compounds are synthesized. Estab-lished a new method of synthesis of tertiary amides which und-er the palladium catalyst, two kinds of carbamoylsilane carbon-carbon cross-coupling reaction with benzyl halides generatedsecondary amides.