chem 109 cfall 2014 armen zakarian office: chemistry bldn 2217! chem 109 c...
TRANSCRIPT
Fall 2014���
Armen Zakarian�Office: Chemistry Bldn 2217!
Chem 109 C �
http://web.chem.ucsb.edu/~zakariangroup/courses.html!
Carbohydrates: Fischer projections manipulation of Fischer projections:�
OOHHOHHOHHOH
D-ribose �
OHO HHO HHO HHO
also D-ribose �
Carbohydrates: Fischer projections
manipulation of Fischer projections:�
OOHHOHHOHHOH
D-ribose �
OHO HHO HHO HHO
also D-ribose � not D-ribose �
O OH
H
OH
H
OH
H
OH
an alditol�
Carbohydrates: Reactions with Bases O
RRO-
RH
R
H HB: + B-H
fundamental reactivity!
base-catalyzed epimerization: D-glucose and D-mannose �
enolate formation:Section 18.2
Carbohydrates: Reactions with Bases O
RRO-
RH
R
H HB: + B-H
fundamental reactivity!
base-catalyzed enediol rearrangement: D-glucose and D-fructose �
Carbohydrates: Reduction fundamental reactivity!
O
R R
O-
R RH-: H
an alditol�
Carbohydrates: Reduction fundamental reactivity!
O
R R
O-
R RH-: H
Carbohydrates: Reduction fundamental reactivity!
O
R R
O-
R RH-: H
Carbohydrates: Oxidation
an aldonic acid�
Carbohydrates: Oxidation
“Tollens test”
Carbohydrates: Oxidation
an aldaric acid�
“Tollens test”
Carbohydrates: Oxidation
PROBLEM 9� Show how an enediol rearrangement can move the
carbonyl group of fructose from C-2 to C-3�
OOH
HHOOHHOHHOH
D-fructose �
Carbohydrates: Lengthening the Chain fundamental reactivity!
OR
RC N+ -O
R
R
N Kiliani-Fischer synthesis:
Steps/Reagents: 1. NaCN, HCl; 2. H2, Pd/BaSO4
3. HCl, H2O
Carbohydrates: Shortening the Chain fundamental reactivity!
Wohl degradation: OR
RC N+-O
R
R
N
OAcHHAcO
N
H OAcOAcHOAc
H OAc
Steps/Reagents: 1. NH2OH; H+ 2. Ac2O, 100 oC
3. NaOH, H2O