Addiction to C-C Hetero Multiple Bond

5Addition to Carbon- hetero multiplebond (Formation of C-C bond )In organic synthesis addition to carbonhetero multiple bond is the basic root toformation of C-C bond . The synthesis toC-c bond love most common example isadd of enolate to the carbon oxygenmultiple bond. since one C should bee- deficient electrophilic nature and secondcarbon should be e- rich neecleophilicnature a The inolates are -vely chargedattracting multiple bond like C=O, EN,carbanion containing adjacent electronNo2 These groups stabilise the -ve charge ofunolate by delocalisation for the formationof evolate such compounds must containat least one R- hydrogen atom war. to thesegroups and it is the x-hydrogen atomwhich is deperotonated on reacn with base.and it is also a method of generationof carbanion Deprotonation carried outfrom such 7 compounds on treating withstrong basedi0-+ o- RR LOHTcCitCCcR-tbaseHResonance stabilisationin inolateLCC=C=N + NH1i]NH3+/H Add? of these enolate (nu adad) at unsaturated ic=o (carbonyl compounds) or at CEN develop c-c bondEformation of (-cbond)Reduction of x=0 of metal hydrides (NaBHy LiAlHy)These metal hydrides reduce aldehyde or Ketones intoalcohol by transferring hydride ion from tetrahydrateof metal to the casbonyle carbon atom and form alloaymetal hydrite intermediate These reduction carriedout in ag or alc. solvent where these metal allowidessolvated 2 reduce into alcohol.NaBHyNaH-HLiACHyLit H Al HIt4RX=0RStRRH-B+P - -BHofBHR HRRH 2HRi,RRyCHKHOH of4RTHRRRxCH-OHRRRof BHHOGHSRR H 3BloH)0°alcoholRIt is clear from above mechanism that 1 moveof NaBHy reduce 4 moles of carbony molecule.NaBHy is regioselective reducing agent reducecarbonyl group , arye chloride into alcohol butdoesn't reduce C=C, CEC , CEN, Nog If the two c=0 prount in same one molecule is non one inconjugation then it reduce only non -conjugated e=dof C=C and -conjugatedCH-4thNa BHY cy CH=CH CH2 only itconjugated non-conjugatedLiAlHy is a true metal hydride and it ismore powerful than NaBHy and reduce all multiplebonded groups except definic and acetylinic badThe methodology of redn just like NaBHy bytransferring hydriche ion to carbon atom ofcarbonyl group.LiACHYLit + ACHL4RCR3Rx=0H Al H+S-RAetsR0HRSt-Alkoxy Alu.4 OH4404R)CHAlRtrihydrideCH OH + LiOH +ACCOH)RRExamples Reactions of Formation of newC-C bondwhich new C-C bond form. most ofThere are numbers of organic reactions insuch reactions observed in nucleophilicaddition to the carbonyl compound /Aldol Reaction and condensationIt is the reaction of two moles of aldehydesor ketone in containing at least one d hydrogenatom presency of dilute alkali, theadd takes place and form p-hydroxyaldehyde or Ketone They are calledaldol or Ketol respectively and the reachknown as aldol reach04it/CH5 EH +-CH-CH=0CH2 - -CH-C45-CHFOBhydroxyaldhydeoff0dCTdil 54iHofC-CH31 HCH CH3CH2CH3EMcthB-nydroxy ketone (ketel)OH-B ddilNaOHdct--tt- CHCHINSHOCH-CHG-CH + CH-CH2- CH=OCH3The add" of two moles and formation of Bhydroxy adduct is known as aldol additionor aedol reaction The adduct on condensationreadily x, B unsaturated loose H2O aldehyde molecule or and ketone form is knownas Aedol condensation The T bond between& and B carbon atoms become quite stabledue to conjugation with carbonyl group- dit-NaOHOHCH-CH thuch CH=0ctf CH-CHo3s-H3OBctfCH-CH- CH r Ct Cx. B unsaturatedaldenydeoBxdilonctz H-CH + CH2-CHB-CH=COHLctf-cff CH- CH CH=OBCH3A-HoCH-CH- 2 CH= GHOCH=OMechanismCH3Alkali or base abstract proton from x-carbonatom of one molicule and form enolateanion the carbanion which acts as anucleophileHo + H--CH3-CH=0HOH +CH2-CH=0,in ECH-OThe enolate Nu undergoes nucleophilic add"to the second mole DATE-(Niodd?)iof - St OH + :CH 2CH=UCtz - CH CH 2 CH=oxide ionThe oxide iow takes the X-H atom of firstmole present in basei°Ht fromOH, 4LCH-CH- CH 2 - CH=OCH3 CH B CH-CH=OHOH- on(Aedol)It is the Aedd Add . Aedol on heatingreadily loose water molecule and formstable L,B unsaturated old carbonyl compoundIt is called aldol condensationOHH- H2OBCH - CH- CH- CH=0 A CH5 CH=CH CH=0crotonaldehydeCrossed Aldol CondensationIt is the addition reac between two differentmoles but atom isknown asOFDil. 04in2oz CH + --CHOCH-CH - CH-CH=03BCH2mixed AedolBut in mixed aldol add the mixture offor aldol always form. The remaining three Aldol are possible from -/from enolate of acetaldehyde withperopanaldehyde04POHCHE - CH + H-CH-CHFO CH CHg B CH 2 cth 2 CHEO2from enolate of acetaldehyde withacetaldihyde.OFPHCH-CH + H-CH-CH=03from enolate of propanaldehyde withperspanaldihydi.ofOHCH CH-CH + CH-CH-C 2 CH=03CH-CH CH CH-CH=03BCHIn crossed aldol condensation and formationof two crossed aldol which one will begood yield Since aldol addn is Nucleomore readily form and also withphilic add" and which melecule wellbe more reactive towards nuchophilicwords it means the less reactive moleculeadd will have B-hydroncy group. anotherundergoes emolisation and more reactivein above case L.H atom of propanaldehydemolecule undergoes nucleophilic addn. so,migrate to the oxygen atom of more reactive acetaldehyde . Between aldehydeand ketone the a-H atom of less reactiveketone will migrate to the oxygen atomof more reactive aldehydeDie OHOHDOFCH5-C+ CH-CH =0Ctf CH cty- 0-CH3CH3morereactive)Ketoaldol(less xartice)Claisen - Schmidt Reac"It is the reacn of aromatic aldehydelacking of a H atom with alathydeas ketone containing d-H unsaturated atom in presenceof base , for L,B aldehydeor ketone .GHHOONa+BGHF-CH=O.+ H-CH-CHEOCHH-CH=CH-CH-O-402cinnamaldenyde4 H5 + If it -8H5 or 8H5 CH=CH-E-GYNaNH2CH = 0 C(Acetophenone) (0) cinnamyl phyelketone(Benzylidenebenzophenone) DATEMechanismIt is the copy of Aldol addition whereenolization takes place and enolateundergoes nucleophilic addn to thearomatic aldehyde form 1- hydroxyproduct which readity loose water moleculeand form L-B unsatirated product.SH5 ot H/- CH-CH=OS H5OH+ 15-CHEO(enolateNy- -GFNuon8H5 of + :CH 2 CH=0 addn 8H5 2CH-4-44-0Ht fromg 2404iHC6H5 CH- - (H. CH=OBL2-H0of1B28H5 CH = CH-CH=0cinnamalchehyde. Knevenegel Reac"It is the xacn of aliphatic or aromatic corbonylcompound with the compound containingactive H atom specially reactive methyunecompound s. in the presence of base formL I B unsaturated carboxylic acid The reactivemethyline compound commonly used are malonicester or ethyl acetoadateBcoortG HgoNaC6H5CH CH COOHEH-CH=O + CH2H1O, -co2Cinnamic acidcoort011CH0B dR CH= 0 + CH32R-CH=CH-COOHcoortTo COOH,(EAA)- -EtoHMechanismThe Mechanism of the reacn become atsame pattern as previous reactions . It isthe nucleophitic add? at ic=0 and form newd, B unsaturated linkage. EAA and diethyemalonate having reactive ionisable H atomin methylene group containing electronattracting 0 group at both the siteactive methyline compounds whentreated form carbanion with base unreadity which loose acts proton as and anucleophilic xagent coortSH5 0 + Him CHSH50H-OEA-outcoortra o etHCH-O-ELGetout(Resonance stabilizationof evolate ion 9In second step the inolate Nu undergoesform oxide ion with new d, B carbonnucleophilic add" at carbonyl carbon atombond. The oxide ion abstract Ht of enolatefrom base and form B-hydroxy compoundwhich readily loose water molecule andform LIB unsaturated bond.coort Nu add08H CHEOcoort+ CH5st S-L6H5-CH-CHcoortcoostH+ from BaseorH5OH245026dB2coortCHHS CH= CH COOH8H5HcoortLas $ unsaturated acidA-H2OCO2DcoonH 0coortCOOHC6 H5 CH=unstable-set 04coort loose the coollMechanism 2c-ch3CH3GH50 HTOCHSH50H +HcooubcolorI-CHboat- same-PQC-CH3CHoutAll these nuchophilic addn reac are catalysed(NO, CN ,-COOH ) they theby presence of electron since attracting increase groupschange at carbonyl carbon atom so rate ofnucleophilis attack increase while electronattracting group decrease In aromatic be carbonylcompound -I group should presentpositionsat ortho and para positions which are dominating Claisen Condensation ReactionIt is the condensation of two moles ofthe esters containing at least two aH atomin presence of stroing base and form reactivemethyline esterOFGH5ONaaCH- C Fogts + 4-cy -SHJOHaisCH-C-CH-C-OSH2(EAA)MechanismIt is also an example of nucleophilic addat '==0 of ester compound The onebase attack and generate >=0 of withmole of ester undergoes enolisationcarbanion Nu whichon second molecule andtotal mechanism given as below :itSH504 +: ct 1-2 out-Poctcth(-Nu) anlistONutaddOFCH3G7+CH22-0945cy--cth0645OC2HSSOGHSSH50Ht of SH50H- SH50192OCH2ofOSH5AE)etc.Benzoin CondensationIt is the condensation of two mole ofbenzaldehyde in presence of KCN sel thebenjain formed by migration of AldehydicH-atom of one male to the aldehydico-atom of second mole The condensationis aromatic counter part of Aldol condensationOFKCNSolOHitOF8H5 CH to H C 8H58H5CHC845BenzoinMechanismK-CNkt + CENS- (sol)EEinGH5 H + :CN6H5HStACN MIS04C6H58H5C=NC=s-OHN4 add"0.04pGHs+8Hg4H5CH8HCNHCNOH,CHHCH- 8H5CN-CNHC6H5CH- CHHBenzoinBurzoin condensation is example ofNucleophilic add' reacn in which one moleacts as a Nu and second molecule astas H a nucleophile accepter- The aldehydicmolecule aldehydic oxygen of Nu- acceptorto atom of nucleophile molecule migrateSince it is nucleophilicelectron addn so seaven speed up by priesence ofspeciallyattracting groups (INO', CN etc)present at o or P positionin theRing LongWitty Reac"It is the reac" of aldehyde or Ketone withcompound The reac better takes place withmethylene and form definicaromatic aldehydes and ketonesAst (GHS) P= CH2CH +2(8H5)P:0Triphenylpharphine3Phasphomethylinerans8HSGH5+PhzP=CHCH+ PhzP=HH2styreneMechanism+kPhzPCbl2methyleneylide formform6H5+O+ Ph3 P-i4H54StS-(NuT)HCHRPh32( Betained intermediateDipolarGHs CH=CH29+p-ph38H5KtosyrineH&cifyPPh3 PROCEDATEThe reagent triphenge phosphine methylinemethyline exists in form two raionating ylide forms form - the Thespecies and behave as aioni ylide form is the attacking toattack carbonyl group The dipolarintermediate folm which is known asinto Betained four structure centered and T.S. immediately The T.S become changeproduct readily collapped form stableand less stable due to the strain to on the reingAdd of Organomitallion on tc = OOrganoretallic compounds L 4i, mg, Zn), theorganic past acts as a nucleophile andgive addn reac" at X=0 The all reactis same manner but rate of reac' maybe differ due to ionic character of cmbond more the metallic nature ofmetal ( Li> mg 7 Zn) more will be ionicnature reac and more will be reactivity of& stS- StS- StR-li R-mgR Zn-RReactivity decrease DATEcarbonyl groups and form alcoholsorganometallics undergoes nucleophilis addndecomposition ofadduct Thebyvarious degreealcohols formsdependinguponnatureof=0 groupwhetheraldehydeorketoneS-StNu add?OH130/180+ /dilHu/R Mc-MNHtHOH1st 5RWpJHOMadductstorthofJaviswroteretimeOHatbioscritibleswillquazofiredualRstatch.treeHR CHOH obserspirdmuintiDearasJanRc.bwisRXHOH2R-mg-HRcrisalsbasistabosit soR.asRRevives rialsRx OHwerRworldvisionletterywaweto trupar sett0storycuseltarlamoliSt8H54HOH birestyOHHt-LionPhy Phenylcyclohesanol DATEAdd n to L, B unsaturated KetonesIn these Retones price Retonic group presentin conjugation to C= and helpin distingtion of organo Lithium compoundfrom Geignard reagent and Franklandhighly than other two compoundsreagent reactiongrans Lithium compounds aredue The rate to high polarity become is c-Li bondand of add at very fastmolecule immediately ketone cam't >coo conjugate andcarbonyl group This addition said tobe 1,2 addGrignard X Frankland reagent arenot so reactive as organs Lithiumcompounds and rate of sear becomeas slower. the During a addn of these reagentsof Nu in Ist step takesplace the conjugation in molecule becomefaster than rate of reach so rest part ofmolecile the reagent at on rearranged conjugatedsaid to be and 1,4 is addn this > way add+2for soS- St Nu addn04R-CH=CH &B8H5 + CH34RCH=CH,c8H5St(Ist step)CH3L, Bunsat. ketone(122-add)Uis(Iststep)writeindil HClCH-mg-xbirtwaterBO-HdRCH=8H5isCH3R-CH = CH-8H5unsaturated ale.St410440omgx+css ng xRCH238H5RISHING(1i4 4addCH3845,conjugationHOHiR--GH5TautomeriseO-HR GHca&H5CH,rrolpwestCH329allJan saturated Retonevilleenotform(unstable)quang guradus toMabusbillingR PAGEReformatory ReacIt is the reach of carbonye compoundsto L haloesters in presence of Znmetal in ether solvent form 2,Bunsaturated ester or Acid alsoa it Znt A B x OF=canoutEthisx,B unsaturaesta130+B&orC-CHC-OHa, B unsaturatedMechanismacidThe Reac takes place through the formationof ester subs tituted organozine compound -then reacn mechanism is usual neucleophilic add at carbonye group.isetherSt S- OFBr-th-c-out + zneBr- an 4/2 2 outorgano zinc comp. CHHSCsoSt's-C6H5oznksBr-2n-ctf-outStS-HHcicocet120OHitC6HecoolT10AB2ofCH= CH-C-OEtEthylcinnamate41 unsat.eslaHotC2H504a8H5CH- CH- C -OHfolmomcinnamic acid(a, B unsaturatedacid