Tua Electrophilic i roto i te Chemistry Organic

Hoki tauhohe tua āhuatanga e te hanganga o te pūhui matū i ngā rauemi tīmatanga e rua, neke atu rānei. A feruri i te huarahi o te tua electrophilic ki te tauira watea o ngā waiwaro rua - hamanga waiwaro acyclic ki tetahi here rua. I tua atu ki a ratou, tangohia i roto i taua panoni atu waiwaro he here maha, tae atu huringa.

Wāhanga te tauhohe i te rāpoi ngota tīmata

tua Electrophilic e wahi i roto i te maha o ngā wāhanga. Electrophile he mahi pai tiaki hei acceptor irahiko, me te here rua o te rāpoi ngota waiwaro rua - hei kaituku irahiko. Ko te pūhui e rua hanga he matatini p-ahua tuatahi. Na ka tīmata te huringa o te π-matatini i roto i te ϭ-matatini. Carbocation hanganga i tenei wā, me tona pūmautanga whakatau i te auau o te ngā i roto i te whānui. Muri tauhohe carbocation tere ki te kanohi nucleophile tōraro whakatupato me te hua faafariuraa whakamutunga i hanga.

Pānga o substituents i runga i te auau tauhohenga

Akona te delocalization (ϭ +) i roto i te carbocation tei reira ki runga ki te hanganga rāpoi tuatahi. pānga pai inductive e faaite rōpū alkyl, arata'i ki te hekenga i roto i te tiaki ngota waro pātata. Ka rite ki te hua, i roto i te rāpoi ngota ki te irahiko foaki substituent faarahi te vairaa papû o te māraa ļa π-irahiko kiato he tika, me te tauhohenga o te rāpoi ngota rite te katoa. Pānga i runga i te tauhohenga o acceptors irahiko ka kia ritenga.

Ko te tikanga o te hononga kōnakonako

E hi'opoa tatou i roto i te kōrero atu te huarahi o te tua electrophilic o te waiwaro rua ki te tauira o te taunekeneke me te kōnakonako.

1. huarahi kōnakonako rāpoi ngota te here rua i waenganui i ngā ngota waro me te kë. Nā ki te tiaki wāhanga pai i tetahi pito o te kōnakonako rāpoi ngota faaho'i te irahiko π-here. Mai i reira he he hanganga o te iu π-matatini.
2. I roto i te taahiraa i muri mai hono matūriki electrophilic ki ngā ngota waro rua, hanga he mowhiti. He he he huringa "onium" katote.
3. tali te toe kōnakonako matūriki i ako (nucleophile pai whakatupato) i te katote onium me hono i te taha ki te ritenga atu i te kōnakonako matūriki o mua. Puta hua whakamutunga - trans-1,2-digalogenalkan. Waihoki, āpitihanga puta i te kōnakonako cycloalkenyl.

Ko te tikanga āpitihanga waikawa hydrohalic

tua Electrophilic o halides hauwai me te waikawa pungatara puta te kore. I roto i te taiao waikawa te dissociated ki te anion te māraa, me te kaiwhakahohe. katote pai whakatupato (electrophile) patu te π-here honoa ki tetahi o nga ngota waro. Kei te hanga e Carbocation, ai te pai whakatupato te ngota waro pātata. tauhohe carbocation muri ki te anion ki te hanga i te hua whakamutunga o te tauhohenga.

Ko te aronga o te tauhohenga i waenga i te tauhohenga me te nuinga o asymmetrical Markovnikov

tua Electrophilic i waenganui i nga rāpoi hangarite e rua puta regioselectively. tikanga o tēnei e hanga e nga poinanaha taea e rua kei te pai noa kotahi. whakaahua ana Regioselectivity tikanga o Markovnikov, kia rite ki nei piri te te hauwai ki te ngota waro hono ki te maha nui o te tahi atu ngota hauwai (atu hydrogenated).

Hei matau tenei ture, he mea e tika ana ki te haamana'o e, tei te auau tauhohe i runga i te pūmautanga o te carbocation takawaenga. Pānga o te irahiko kaituku me te acceptor substituents whakahuatia i runga ake. Ko te kupu, tua atu electrophilic o te waikawa hydrobromic ki te pōwaro mata ki te hanganga o te 2-bromopropane. Ko te māraa ļa takawaenga ki te tiaki pai i runga i te ngota waro pokapū atu eu carbocation ki te tiaki pai i roto i te ngota tino. Ka rite ki te hua, ähua he ngota pūkeha te ki te ngota waro rua.

Pānga o substituents irahiko-kati i runga i te akoranga o te pāhekoheko

Ki te kei te muingota taketake irahiko kati substituent e he inductive tōraro pānga mesomeric me / ranei, he tua electrophilic ki te ture i runga ake. Tauira o taua substituents: CF _3, COOH, CN. I roto i tenei take, te nui te tawhiti o te tiaki pai o te irahiko rōpū kati tuatahi hanga he carbocation atu eu. Ka rite ki te hua, hauwai hono ki waro ngota iti hydrogenated.

ka titiro putanga Ao o nga ture, ano tenei: te pāhekoheko o te waiwaro rua hangarite me te hangarite puta kaiwhakahohe tauhohenga i ara o hanganga o te carbocation tino pūmau.