97506-01-9Relevant academic research and scientific papers
Diastereoselective ritter-like reaction on cyclic trifluoromethylated N,O-acetals derived from L-tartaric acid
Jamaa, Abdelkhalek Ben,Grellepois, Fabienne
, p. 10360 - 10375 (2018/05/31)
Despite the presence of the highly electron-withdrawing fluorinated substituent, cyclic α-trifluoromethylated N-acyliminium ions were successfully generated from fluorinated O-acetyl-N,O-acetal L-tartaric acid derivatives. The addition of nitriles on these intermediates occurred with high to excellent syn diastereoselectivity and led, in most cases, to oxazolines and amides as single diastereomers. The diastereoselectivity of the addition and the nature of the reaction product depend on the substituents on the hydroxyl groups of the tartaric acid scaffold. This methodology gave access to enantiopure, highly functionalized 5-(trifluoromethyl)pyrrolidin-2-one derivatives, bearing the fluorinated substituent on a tetrasubstituted carbon.
Asymmetric synthesis of gem-difluoromethylenated dihydroxypyrrolizidines and indolizidines
Thaharn, Watcharaporn,Bootwicha, Teerawut,Soorukram, Darunee,Kuhakarn, Chutima,Prabpai, Samran,Kongsaeree, Palangpon,Tuchinda, Patoomratana,Reutrakul, Vichai,Pohmakotr, Manat
, p. 8465 - 8479,15 (2020/09/15)
An asymmetric synthesis of gem-difluoromethylenated dihydroxypyrrolizidines and indolizidines is described. The fluoride-catalyzed nucleophilic addition of PhSCF2SiMe3 (1) to chiral imides was achieved in satisfactory yields to provide mixtures of syn- and anti-isomers 6-9 with moderate to good diastereoselectivities. Reductive cleavage of the phenylsulfanyl group followed by intramolecular radical cyclization of the syn-isomers 6-9 occurred under refluxing conditions to afford the corresponding gem-difluoromethylenated 1-azabicyclic compounds 10-13 in moderate yields as a separable mixture of cis- and trans-isomers. The cis-isomers of compounds 10 and 12 and trans-13 were readily transformed to gem-difluoromethylenated dihydroxypyrrolizidines 20 and 27 and indolizidine 28, respectively, by reductive cleavage of the hydroxyl group and organometallic addition followed by hydrogenolysis.
Inexpensive, multigram-scale preparation of an enantiopure cyclic nitrone via resolution at the hydroxylamine stage
Thiverny, Maryse,Demory, Emilien,Baptiste, Benoit,Philouze, Christian,Chavant, Pierre Y.,Blandin, Veronique
experimental part, p. 1266 - 1273 (2011/11/30)
The reduction of the chiral, racemic nitrone MiPNO provides a secondary hydroxylamine. Its O-acylation with O,O'-dibenzoyl-l-tartaric acid anhydride gives two diastereomers, that can be easily separated by selective dissolution in orthogonal solvents. The recovery of the enantiopure nitrone is then carried out in a single step. The process allows the straightforward isolation of (R) and (S)-MiPNO in 57% and 38% yield, respectively, from rac-MiPNO.
Design of branched and chiral solvatochromic probes: Toward quantifying polarity gradients in dendritic macromolecules
Milosevic, Petar,Hecht, Stefan
, p. 5023 - 5026 (2007/10/03)
(Chemical Equation Presented) A pair of chiral, branched monomer building blocks, consisting of a solvatochromic probe and a spectroscopically inactive volume dummy, has been developed. The probe can selectively be excited, and its fluorescence characteristics provide information about local polarity. Incorporation of these monomers into high-generation polyester dendrimers should enable a detailed investigation of the polarity/density profile in dendritic architectures and ultimately allow for the realization of energy gradients from one chromophore building block only.
Acyliminium cyclization of several chiral N-alkenylsuccinimide derivatives
Ohwada,Inouye,Kimura,Kakisawa
, p. 287 - 289 (2007/10/02)
The acyliminium intermediate derived from (3R,4R)-N-(3-butenyl)-3,4-bis(benzyloxy)succinimide cyclized to give (8aS)- and (8aR)-hexahydro-3(2H)-indolidinone derivatives. On the other hand, those derived from N-3-hexenyl derivatives afforded (8aS)-hexahydr
