Kinetic Resolutions - The Stoltz Group
Kinetic Resolutions - The Stoltz Group
Kinetic Resolutions - The Stoltz Group
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(±)-<br />
(±)-<br />
R S<br />
RL<br />
O<br />
R 1<br />
O<br />
R 2<br />
O<br />
R 2<br />
O<br />
25-75 mol% Catalyst 16<br />
O O<br />
O<br />
2.3 eq Oxone<br />
9.5 eq K 2 CO 3<br />
CH 3CN / DMM<br />
Na 2 B 4 O 7 in EDTA (aq)<br />
-20 to 0 o C<br />
R 1<br />
More Shi Epoxidation<br />
R<br />
TMS<br />
1 = Alkyl, OMe, OTBS, OTMS<br />
R 2 = Ph, OPiv,<br />
s = 11-61<br />
vs.<br />
O<br />
R 1<br />
O<br />
O<br />
R 2<br />
O<br />
R 2<br />
O O<br />
Favored enantiomer Disfavored enantiomer<br />
R M<br />
H<br />
R L<br />
RS<br />
H<br />
R S<br />
R L<br />
RM<br />
R M<br />
R S<br />
H R L<br />
OH OH<br />
H<br />
R M<br />
O<br />
+<br />
R 1<br />
R 1<br />
O<br />
R 2<br />
O<br />
O O<br />
Shi, et. al., J. Am. Chem. Soc., 1999, 121, 7718<br />
Alkenes and Allenes - Sharpless Dihydroxylation<br />
Top (!)- attack<br />
Bottom (")- attack<br />
AD-mix<br />
AD-mix contains:<br />
Cinchona alkaloid PHAL ligand<br />
K 2 OsO 2 (OH) 4<br />
K 3 Fe(CN) 6<br />
K 2 CO 3<br />
+<br />
N N<br />
O<br />
O<br />
Catalyst 16<br />
Et<br />
Et<br />
N<br />
N N N<br />
H<br />
O<br />
O<br />
H<br />
MeO OMe<br />
Et<br />
MeO<br />
H<br />
N<br />
N<br />
O<br />
(DHQD) 2PHAL<br />
(In AD-mix-!)<br />
N<br />
N<br />
O<br />
(DHQ) 2 PHAL<br />
(In AD-mix-")<br />
N<br />
N<br />
H<br />
Et<br />
O<br />
OMe<br />
Sharpless, et. al., J. Org. Chem., 1992, 57, 2768<br />
18