Page 28 - Demo-1

DKR with Boron Electrophiles
O i PrOB
Cy
Cy
O
BO Ph
ClMg
O Cy
Cy
PhCHO
OH
71%, 94% ee
OOBO
100%, >97% de
89%, 94% de
O O
O OLi
OBO
O
ON LDA ON Br ON NaI (cat), 18-Crown-6
Sturmer, R. Angew. Chem. Int. Ed. Engl. 1990, 29, 59 Ward, R. S. Tetrahedron: Asymmetry 1995, 6, 1475
Ruthenium-Catalyzed Hydrogenation of β-Ketoesters
Ru-catalyzed DKR has been developed into a powerful transformation of very broad scope
O O
O
OO
OMe
NHBz
Cl BnO
[RuCl((R)-BINAP)(C6H6)]Cl H2 , 100 atm
[RuCl2((R)-BINAP)]2Et3N H2 , 100 atm
Cl
AcHN
OH O
O H
96% de, 94% ee
OH O
OH
XO [(R)-binap]Ru O
H H3C H
OMe
NHBz N SR
100% conv.
syn:anti = 94:6 98% ee
O carbapenems
OH
Cl
CO2H
BnO
[(R)-BINAP]Ru(II) H2 , 80 bar
BnO
(R)-MeO-BIPHEPRuBr2 H2 , 140 bar
OH O
Cl
90% de, 88% ee
CO2H OO
OEt
O CO2Me
AcHN CO2Me
Ph
Ph
OEt
100% yield, 95% de, 80% ee (enantiomerically pure after two recrystallizations)
diltiazem (a potent channel blocker)
Cl
Noyori, R.; Tokunaga, M.; Kitamura, M. Bull. Chem. Soc. Jpn. 1995 68, 36
O