TY - JOUR
T1 - Diazo Compounds and Phenyliodonium Ylides in the Inter- and Intramolecular Cyclopropanations Catalyzed by Dirhodium (II)
T2 - Synthesis and Chiral Resolution by GC versus HPLC
AU - Ghanem, Ashraf
AU - Lacrampe, Fabienne
AU - Aboul-Enein, Hassan
AU - Schurig, Volker
PY - 2005
Y1 - 2005
N2 - The dirhodium(II)-catalyzed intermolecular cyclopropanation of a set of olefins with either diazo free phenyliodonium ylides or diazo compounds afforded cyclopropanes derived from Meldrum’s acid, dimethyl malonate, (silanoxyvinyl)diazoacetates, 3,3,3-trifluoro-2-diazopropionate, ethyl diazo(triethyl)- and (dimethylphenyl)silylacetate with moderate to high yield in either racemic or enantio-enriched forms. The intramolecular cyclopropanation of triethylsilyl-substituted allyl diazoacetates in the presence of the chiral rhodium(II) catalyst [Rh2(s-nttl)4] in toluene afforded the corresponding cyclopropanes with up to 37% ee. An efficient chiral separation method based on enantioselective GC and HPLC was developed. The method provides information about the chemical yields of the cyclopropane products, enantioselectivity, substrate specifity, and catalytic activity of the chiral catalysts used in the inter- and intramolecular cyclopropanation reactions and avoids timeconsuming work-up procedures.
AB - The dirhodium(II)-catalyzed intermolecular cyclopropanation of a set of olefins with either diazo free phenyliodonium ylides or diazo compounds afforded cyclopropanes derived from Meldrum’s acid, dimethyl malonate, (silanoxyvinyl)diazoacetates, 3,3,3-trifluoro-2-diazopropionate, ethyl diazo(triethyl)- and (dimethylphenyl)silylacetate with moderate to high yield in either racemic or enantio-enriched forms. The intramolecular cyclopropanation of triethylsilyl-substituted allyl diazoacetates in the presence of the chiral rhodium(II) catalyst [Rh2(s-nttl)4] in toluene afforded the corresponding cyclopropanes with up to 37% ee. An efficient chiral separation method based on enantioselective GC and HPLC was developed. The method provides information about the chemical yields of the cyclopropane products, enantioselectivity, substrate specifity, and catalytic activity of the chiral catalysts used in the inter- and intramolecular cyclopropanation reactions and avoids timeconsuming work-up procedures.
UR - https://link.springer.com/article/10.1007/s00706-005-0299-6
U2 - 10.1007/s00706-005-0299-6
DO - 10.1007/s00706-005-0299-6
M3 - Article
SN - 0001-2793
VL - 136
SP - 1205
EP - 1219
JO - A U M L A
JF - A U M L A
IS - 47
ER -