Electrophilic kuwedzera mune Organic Chemistry

Nokuti Uyezve Maitiro dzinoratidzwa paumbwe makemikari kubva pokutangira zvinhu zviviri kana kupfuura. Funga mashandiro ose electrophilic kuwedzera yakakunakira muenzaniso alkenes - unsaturated acyclic Mahydrocarbon chete chisungo kaviri. Mukuwedzera kwavari, mune transformations dzakadaro kutora mamwe Mahydrocarbon rine vakawanda zvisungo, kusanganisira cyclic.

Nzendo kuita kuti kutanga mamorekuru

Electrophilic Kuwedzera kunoitika mumatanho dzakawanda. Electrophile Kuva nemaonero mutariri mabasa ave Erekitironi acceptor, uye kaviri chisungo ane alkene Morekuru - ive Erekitironi anyatsoronga. The yeimwe maviri vanoumba yokutanga S.-yainge yakaoma. Zvadaro anotanga kuchinja π-dzakaoma ϭ-kunzwisisa. Carbocation inotungamirwa Panguva iyi uye chacho hachichinji kuona mwero nekuita zvavo. Zvadaro carbocation zvaanoita nokukurumidza pamwe haasaruri isakarurama mhosva nucleophile uye yokupedzisira kutendeuka chigadzirwa aumba.

Mugumisiro substituents pamusoro kuita mwero

Akamurairawo delocalization (ϭ +) mukati carbocation napo kwokutanga samolecular marongerwo. Positive inductive mugumisiro iyo inoratidza boka alkyl, kunoita kuti vasanyanye mhosva pedyo kabhoni atomu. Somugumisiro, iri morekuru pamwe Erekitironi rizowedzerwa substituent kunowedzera hama kutsiga nokuo- nga π-Erekitironi arambe achirema wakakodzera uye reactivity pamusoro Morekuru rose. Zvainoita reactivity kuti Erekitironi acceptors vachava akatarisana.

The mashandiro pamusoro halogens kubatanidza

Ngationgororei muudzame ari mashandiro pakati electrophilic Kuwedzerwa alkene kuti muenzaniso nekuita halogen.

1. Halogen Morekuru anosvika kaviri chisungo pakati kabhoni maatomu uye inobudisa. Nokuda ubatanidzwewo zvakanaka vaichengeta imwe mugumo morekuru halogen kuminyuka ari maerekitironi π-chisungo. Sezvo pane inotungamirwa chisina kutsiga π-kunzwisisa.
2. In danho rinotevera electrophilic PARTICIPLE zvakabatana kabhoni maatomu maviri, pova rin'i. Pane cyclic "onium" Ion.
3. The yasara mhosva PARTICIPLE halogen (chokwadi mhosva nucleophile) iri vakaita pamwe onium Ion uye anobatana pakatarisana kubva yapfuura nezvimedu halogen. Anozviratidza kwokupedzisira chigadzirwa - mhiri-1-2-digalogenalkan. Saizvozvowo, kuda kunoitika nokuda halogen cycloalkenyl.

The mashandiro kuda hydrohalic acids

Electrophilic kuwedzera rehydrogen halides uye sulfuric asidhi kuitika kudaro. Munzvimbo acidic ezvinhu ari dissociated kuva nokuo- nga uye reagent anion. Chokwadi mhosva Ion (electrophile) inorwisa kuti π-chisungo machira mumwe kabhoni maatomu. Carbocation aumbwa, sezvamakaropafadzwa pedyo kabhoni atomu iri chokwadi mhosva. carbocation Next zvaanoita pamwe anion kuumba chokupedzisira zvibereko kuita.

Kutungamirirwa zvakaitwa pakati reagents uye kazhinji asymmetrical Markovnikov

Electrophilic kuwedzera pakati maviri asymmetric mamorekuru kunoitika regioselectively. Izvi zvinoreva kuti vaviri zvichibvira isomers aumbwa zvinganaka chete. Regioselectivity anorondedzera Kutonga Markovnikov raMwari, maererano iyo hydrogen wanamatira imwe kabhoni atomu chokuita vakawanda vamwe rehydrogen maatomu (more hydrogenated).

Kuti tinzwisise mutemo uyu, zvakakosha kuyeuka kuti maitiro mwero kunoenderana kutsiga zvenguva carbocation. Mugumisiro Erekitironi anyatsoronga uye acceptor substituents ataurwa pamusoro. Saka, electrophilic kuwedzera hydrobromic asidhi kuti propene kutungamirira kuti paumbwe 2-bromopropane. The zvenguva nokuo- nga uine mutariri pamusoro nechepakati kabhoni atomu itsige carbocation uine mutariri kwazvo atomu. Somugumisiro, mumwe bromine atomu iri vakaita ane yechipiri kabhoni atomu.

Mugumisiro Erekitironi-dzirege substituents pamusoro weboka kudyidzana

Kana yepakutanga Morekuru rine Erekitironi dzirege substituent iro rine kunaka inductive uye / kana mesomeric chaizvoizvo electrophilic Kuwedzera runorwisana pamusoro mitemo. Mienzaniso substituents dzakadaro: CF _3, COOH, CN. Panyaya iyi, chikuru daro zvakanaka vebasa chikuru Erekitironi dzirege boka anoita yakatsiga zvikuru carbocation. Somugumisiro, rehydrogen zvakabatana kabhoni atomu shoma hydrogenated.

Universal shanduro mitemo achatarira seizvi: kubata ane asymmetric alkene uye asymmetric reagent maitiro unobuda nenzira paumbwe mudanga kupfuura carbocation.