Chương 1 Phản ứng của các hợp chất carbonyl l.Phản ứng cộng ái nhân
2 Phản ứng thê vào vị trí alpha của nhóm carbonyl
3 Phản ứng ngưng tụ aldehyd và keton (phan ung aldol) 4 Hợp chât ơ,B-không no carbonyl
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Có bao nhiêu nguyên tử H-alhpa trong phân tử các chât sau đây :
(a) 3,3-Dimethyl-2-butanone (c) Benzyl methyl ketone (b) 2,2-Dimethylpropanal (d) Cyclohexanone
Trang 10Overall reaction: O OH | H,0* | RCH;CR: RCH= CR’
Aldehyde or ketone Enol
Step 1: A proton is transferred from the acid catalyst to the carbonyl oxygen
=
Thy SÀN HO H cm _ :O—H | ⁄ H
RCH,CR: === RCHCR: + :Ố:
H H
Aldehyde Hydronium Conjugate acid of Water or ketone ion carbonyl compound
Step 2: A water molecule acts as a Bronsted base to remove a proton from the a carbon atom of the protonated aldehyde or ketone
— H mà H
slow +
RCH op == RCH=CR’ + H—O:
re ot H
Conjugate acid of Water Enol Hydronium carbonyl compound ion
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Overall reaction: O OH | HO” | RCH:CR/ RCH+=CR’
Aldehyde or ketone Enol
Step 1: A proton is abstracted by hydroxide ion from the a carbon atom of the carbony! compound T1 SK slow 'Ñ KL RCH—CR' + 70: === RCH—CR' + :Ó: ¿| 7 = N | H
Aldehyde Hydroxide Conjugate base of Water or ketone ion carbonyl compound
Step 2: A water molecule acts as a Bronsted acid to transfer a proton to the oxygen
of the enolate ion
a: =H
Xv fas .e—
RCH=CR’ + 30: =——= RCHECR' + :Ö: ⁄ ⁄
H H
Conjugate base of Water Enol Hydroxide
carbonyl compound ion
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Chương 1 Phản ứng của các hợp chất carbonyl
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4 Hop chat ơ,B-không no carbonyl