129398-25-0Relevant articles and documents
Synthesis of fluorine-containing cyclic amino acid derivatives via ring closing olefin metathesis
Osipov, Sergey N.,Bruneau, Christian,Picquet, Michel,Kolomiets, Alexey F.,Dixneuf, Pierre H.
, p. 2053 - 2054 (1998)
New N-protected α-CF3 amino esters with two alkene chains (1,7-dienes 3 and 1,6-dienes 5) were reacted with the ring closing metathesis catalyst Ru=CHPh(Cl)2(PCy3),2 to give the α-CF3 dehydropipecolin
Ruthenium-catalysed synthesis of fluorinated bicyclic amino esters through tandem carbene addition/cyclopropanation of enynes
Eckert, Matthieu,Moulin, Solenne,Monnier, Florian,Titanyuk, Igor D.,Osipov, Sergey N.,Roisnel, Thierry,Derien, Sylvie,Dixneuf, Pierre H.
scheme or table, p. 9456 - 9462 (2011/10/02)
The reaction of fluorinated 1,6- and 1,7-enynes, containing the moiety N(PG)C(CF3)(CO2R), with diazo compounds in the presence of [RuCl(cod)(Cp*)] (cod=cycloocta-1,5-diene, Cp=C5Me 5, PG=protecting group) as the catalyst precursor leads to the formation of fluorinated 3-azabicyclo[3.1.0]hexane-2-carboxylates and 4-azabicyclo-[4.1.0]heptane-3-carboxylates. This catalytic transformation was applied to various protecting groups and has proved to be a selective and a general synthetic tool to form constrained proline or homoproline derivatives in good yields. Z stereoselectivity of the created alkenyl group is obtained with N2CHSiMe3, whereas N2CHCO2Et favours selectively the E configuration for the same double bond. The diastereoselectivity exo/endo depends on the size of the created ring. The X-ray structures of two products have been determined, showing the stereochemistry of the compounds. The reaction can be understood by initial [2+2] addition of the Ru=CHY bond, generated from diazoalkane, with the C≡CH bond of the enyne leading to a key bicyclic ruthenacyclobutane, which promotes the cyclopropanation, rather than metathesis. This selective formation of bicyclic [n.1.0] compounds results from the ruthenium-catalysed creation of three carbon-carbon bonds in a single step under mild conditions. Copyright
Synthesis of fluorine-containing cyclic α-amino acid and α-amino phosphonate derivatives by alkene metathesis
Osipov, Sergey N.,Artyushin, Oleg I.,Kolomiets, Alexey F.,Bruneau, Christian,Picquet, Michel,Dixneuf, Pierre H.
, p. 3891 - 3897 (2007/10/03)
The electrophilic imino esters XF2CC(=NPG)CO2Me and imino phosphonates CF3CC(=NPG)P(O)(OR)2 (PG = SO2Ph, Cbz, Boc) were transformed by nucleophilic and then electrophilic additions into fluorine-conta
The 'non-oxidative' Pummerer reaction: Conclusive evidence for S(N)2- type stereoselectivity, mechanistic insight, and synthesis of enantiopure L- α-trifluoromethylthreoninate and D-α-trifluoromethyl-allo-threoninate
Crucianelli, Marcello,Bravo, Pierfrancesco,Arnone, Alberto,Corradi, Eleonora,Meille, Stefano V.,Zanda, Matteo
, p. 2965 - 2971 (2007/10/03)
Enantiopure methyl D-α-trifluoromethyl-allo-threoninate 18 and L-α- trifluoromethylthreoninate 19 were synthesized using (R)-ethyl p- tolylsulfoxide as chiral α-hydroxyethyl anion equivalent. The key step was the S(N)2-type replacement of the sulfinyl auxiliary with a hydroxy group, via trifluoroacetic anhydride promoted 'non-oxidative' Pummerer reaction (NOPR) of the diastereomeric intermediate β-sulfinyl amines 14 and 15, obtained by condensation of (R)-ethyl p-tolylsulfoxide 13 with the N-Cbz imine of methyl trifluoropyruvate 12. The conclusive evidence for S(N)2-type stereoselectivity of the NOPR was achieved by X-ray diffraction of both the starting diastereomer 14 and the p-bromobenzoate 25, obtained from the threoninate 19. NMR monitoring of the NOPR performed on 15 allowed the detection of a transient intermediate, which was identified as the four membered cyclic σ-sulfurane 27. This intermediate spontaneously rearranged (40 min, rt) into the corresponding sulfenamide 17, probably via an intramolecular displacement of the sulfinyl by a trifluoroacetoxy group, with inversion of configuration at the carbon stereocenter. The same process occurred for the diastereomeric β-sulfinyl amine 14, but the sulfenamide 16 was formed at very fast rate, thus precluding NMR detection of the corresponding σ-sulfurane intermediate 26. One-pot treatment of the diastereomeric sulfenamides 16 and 17 with NaBH4 afforded very good yields of the corresponding threoninates 18 and 19.
