Camphor-based alpha-bromo ketones for the asymmetric darzens reaction
(1R)-2-endo-Bromoacetyl-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol (endo-2-bromoacetylisoborneol) 4 and its trimethylsilyl ether 3 are presented as efficient reagents for the asymmetric Darzens reaction. From the alpha,beta-epoxy ketone adducts the chiral inductor camphor is removed, by treatment with ceric(IV) ammonium nitrate, to yield the corresponding epoxy acids which are isolated as their dicyclohexylammonium salts.
Palomo
C
Departamento de Quimica Organica, Facultad de Quimica, Universidad del Pais Vasco, Apdo 1072, 20080 San Sebastian, Spain, Organisch-chemisches Institut der Universitat Zurich, Winterthurerstrasse 190, CH-8057 Zurich, Swit.
Oiarbide
M
Sharma
AK
Gonzalez-Rego
MC
Linden
A
Garcia
JM
Gonzalez
A