138491-98-2Relevant academic research and scientific papers
Copper-catalyzed domino homologation and cycloisomerization reactions for 3-pyrroline synthesis
Shin, Ye Ho,Maheswara, Muchchintala,Hwang, Joon Young,Kang, Eun Joo
, p. 2305 - 2311 (2014/04/17)
Copper bromide was found to be an efficient catalyst for a domino reaction sequence leading to 3-pyrrolines. The Cu(I)-catalyzed Crabbe reaction of propargyl sulfonamide and selective cycloisomerization of the allene intermediate were carried out using microwave irradiation conditions affording a wide range of 2-substituted- and 2,5-disubstituted-3-pyrrolines. Mechanistic studies of the reaction intermediates revealed two possible reaction pathways; both invoke the importance of vinyl copper intermediates.
Generation of 2-azaallyl anions by the transmetalation of N-(trialkylstannyl)methanimines. Pyrrolidine synthesis by [3 + 2] cycloadditions with alkenes
Pearson, William H.,Szura, Daniel P.,Postich, Michael J.
, p. 1329 - 1345 (2007/10/02)
Treatment of N-(trimethylstannyl)methanimines or N-(tri-n-butylstannyl)methanimines with methyllithium or n-butyllithium, respectively, affords 2-azaallyl anions by tin-lithium exchange. These anions undergo intermolecular or intramolecular [π4s + π2s] cycloadditions with alkenes and alkynes to generate pyrrolidines or pyrrolines after quenching with water or other electrophiles. The tin-lithium exchange method allows unstabilized 2-azaallyl anions to be generated for the first time. The lifetime of the anions is limited by a competing intermolecular side reaction. Therefore, relatively reactive alkenes and alkynes must be used, such as stilbene, styrenes, enynes, diphenylacetylene, vinyl sulfides, vinyl selenides, and vinyl silanes. The latter three types of anionophiles afford functionalized cycloadducts which may be transformed into more useful pyrrolidines by reduction, elimination, or oxidation. A synthesis of the alkaloid (±)-mesembrane was accomplished using an intramolecular 2-azaallyl anion cycloaddition.
