212071-06-2Relevant articles and documents
2-Trimethylsilylethanesulfonyl (SES) versus tosyl (Ts) protecting group in the preparation of nitrogen-containing five-membered rings. A novel route for the synthesis of substituted pyrrolines and pyrrolidines
Declerck, Valerie,Allouchi, Hassan,Martinez, Jean,Lamaty, Frederic
, p. 1518 - 1521 (2007/10/03)
(Chemical Equation Presented) The 2-trimethylsilylethanesulfonyl (or SES) protecting group was compared to the tosyl (Ts) group in the preparation of a nitrogen-containing five-membered ring obtained by the aza-Baylis - Hillman/alkylation/RCM route. While
A Novel [3+2] Cycloaddition Approach to Nitrogen Heterocycles via Phosphine-Catalyzed Reactions of 2,3-Butadienoates or 2-Butynoates and Dimethyl Acetylenedicarboxylate with Imines: A Convenient Synthesis of Pentabromopseudilin
Xu, Zhenrong,Lu, Xiyan
, p. 5031 - 5041 (2007/10/03)
The reactivity of a new three carbon synthon, generated in situ from the reaction of 2,3-butadienoates 2-butynoates with an appropriate phosphine as the catalyst, toward the electron-deficient imines is described. Triphenylphosphine-catalyzed reaction of methyl 2,3-butadienoate with N-sulfonylimines gave the single [3+2] cycloadduct in excellent yield; tributylphosphine-catalyzed reaction of methyl 2,3-butadienoate or 2-butynoate with N-tosylimines afforded the corresponding [3+2] cycloadduct as the major product along with a small amount of the three components adduct. Aliphatic N-tosylimines gave moderate yield for this reaction. In addition, a new phosphine-catalyzed cyclization reaction of dimethyl acetylenedicarboxylate with N-tosylimines is also described. A reaction mechanism is proposed. Further elaborations of the cycloaddition products and the synthesis of pentabromopseudilin using this method are exemplified.
