10 attempts left R-C=CH Alkynes undergo hydroboration to give alkenylboranes, which can be oxidized to give carbonyl compounds with hydrogen peroxide. The net result of the two-step sequence is hydration, which gives aldehydes from terminal alkynes. Check my work 1. R₂BH 2. H₂0₂, NaOH R H H H₂O2 R H BR¹2 Alkenylborane The oxidation step involves an enol intermediate. Using the following mechanism as a guide, draw the structure of the enol that is formed in the conversion of 1-hexyne to hexanal. Click the "draw structure" button to launch the drawing utility.

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Chapter1: Chemical Foundations
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Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
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Alkynes undergo hydroboration to give alkenylboranes, which can be oxidized to give carbonyl
compounds with hydrogen peroxide. The net result of the two-step sequence is hydration, which gives
aldehydes from terminal alkynes.
R-C=CH
1. R'₂BH
2. H₂O2, NaOH
Conversion of an Enol to a Ketone
THE OVERALL REACTION:
H
RCH
Enol
H
Hydronium ion
OH
R'
The oxidation step involves an enol intermediate. Using the following mechanism as a guide, draw the
structure of the enol that is formed in the conversion of 1-hexyne to hexanal. Click the "draw
structure" button to launch the drawing utility.
+RCH:
Enol
Check my work
R
R'
BR 2
Alkenylborane
OH
H
H
THE MECHANISM:
Step 1: In aqueous acid, the first step is proton transfer to the carbon-carbon
double bond.
H₂O2
Ketone
(aldehyde if R' = H)
H
`'R'
H
Water
R
1
:O:+ RCH-
+ÖH
H
R'
H
Conjugate acid
of ketone
Transcribed Image Text:25 eBook Print References 10 attempts left Alkynes undergo hydroboration to give alkenylboranes, which can be oxidized to give carbonyl compounds with hydrogen peroxide. The net result of the two-step sequence is hydration, which gives aldehydes from terminal alkynes. R-C=CH 1. R'₂BH 2. H₂O2, NaOH Conversion of an Enol to a Ketone THE OVERALL REACTION: H RCH Enol H Hydronium ion OH R' The oxidation step involves an enol intermediate. Using the following mechanism as a guide, draw the structure of the enol that is formed in the conversion of 1-hexyne to hexanal. Click the "draw structure" button to launch the drawing utility. +RCH: Enol Check my work R R' BR 2 Alkenylborane OH H H THE MECHANISM: Step 1: In aqueous acid, the first step is proton transfer to the carbon-carbon double bond. H₂O2 Ketone (aldehyde if R' = H) H `'R' H Water R 1 :O:+ RCH- +ÖH H R' H Conjugate acid of ketone
THE MECHANISM:
Step 1: In aqueous acid, the first step is proton transfer to the carbon-carbon
double bond.
H
BOH
H
Hydronium ion
RCH₂
R'
Conjugate acid
of ketone
1-Hexyne
draw structure...
+RCH=
SÖH
Enol
Step 2: The conjugate acid of the ketone transfers a proton from oxygen to a water
molecule, yielding a ketone.
¹H-
H
+ :0:
R'
H
Water
H
:O: +RCH-
H
Water
1. R'₂BH
2. H₂O₂, NaOH
RCH₂
Ketone
R'
R'
H
Conjugate acid
of ketone
+ÖH
+
Hexanal
H
H-O:
H
Hydronium
ion
H
Transcribed Image Text:THE MECHANISM: Step 1: In aqueous acid, the first step is proton transfer to the carbon-carbon double bond. H BOH H Hydronium ion RCH₂ R' Conjugate acid of ketone 1-Hexyne draw structure... +RCH= SÖH Enol Step 2: The conjugate acid of the ketone transfers a proton from oxygen to a water molecule, yielding a ketone. ¹H- H + :0: R' H Water H :O: +RCH- H Water 1. R'₂BH 2. H₂O₂, NaOH RCH₂ Ketone R' R' H Conjugate acid of ketone +ÖH + Hexanal H H-O: H Hydronium ion H
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