1218989-41-3Relevant academic research and scientific papers
PROCESS FOR SYNTHESIS OF 2-SUBSTITUTED PYRROLIDINES AND PIPERADINES
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Page/Page column 46-47; 48, (2011/09/19)
The present invention provides a highly efficient, versatile one-step process for asymmetric synthesis of either diastereomer of 2-substituted pyrrolidines from a single starting material with excellent yields and high diastereoselectivety. Also provided is a method for the asymmetric synthesis of both diastereomers of 2-substituted piperidines with good yields and excellent diastereoselectivety. Diasteroselectivity is controlled effectively by choice of reducing agent.
Asymmetric synthesis of 2-arylpyrrolidines starting from γ-chloro N-(tert-butanesulfinyl)ketimines
Leemans, Erika,Mangelinckx, Sven,De Kimpe, Norbert
scheme or table, p. 3122 - 3124 (2010/09/04)
The enantioselective reductive cyclization of γ-chloro N-(tert-butanesulfinyl)ketimines towards the short and efficient synthesis of (S)- and (R)-2-arylpyrrolidines (ee >99%) is described for the first time by treatment with LiBEt3H and subsequ
A facile asymmetric synthesis of either enantiomer of 2-substituted pyrrolidines
Reddy, Leleti Rajender,Das, Sonia G.,Liu, Yugang,Prashad, Mahavir
supporting information; experimental part, p. 2236 - 2246 (2010/06/15)
Chemical Reaction Reprentation A new and general method for asymmetric synthesis of either enantiomer of 2-substituted pyrrolidines from a single starting material is described. Reductive cyclization of (Ss)-γ-chloro-N- tertbutanesulfinyl ketimines with LiBHEt3 in THF at -78 to 23 °C afforded (Ss,R)-N-tert-buta.nemnnyl-2-substituted pyrrolidines in excellent yields (88-98%) and with high diastereoselectivity (99:1). The diastereoselectivity is controlled effectively by the choice of reducing agent. Thus, the corresponding epimers of (3 to DIBAL-H/LiHMDS. Deprotection of N-fe/ f-butanesulfinyl-2-substituted pyrrolidines using 4 N HCl in dioxane and MeOH gave the corresponding enantiomers of 2-substituted pyrrolidines in quantative yield. This method was found to be effective for a variety of substrates including aromatic, heteroaromatic, and aliphatic substituents. Extension of this methodology to the formation of 2-substituted piperidines is also illustrated. Reductive cyclization of (5s)-3 in THF at -78 to 23 °C or DIBAL-H/LiHMDS in toluene at -78 to 0 °C afforded the (Ss,R?)-N-tert-butanesulfinyl-2-substituted piperidines in excellent yield (98%) and with high diastereoselectivity (99:1) or (Ss,S)-.N-tert-butanesulfmyl- 2substituted piperidines in good yield (98%) and with high diastereoselectivity (1:99), respectively.
