Cycloadditions of Nonstabilized 2‐Azaallyllithiums (2‐Azaallyl Anions) and Azomethine Ylides with Alkenes: [3 + 2] Approaches to Pyrrolidines and Application to Alkaloid Total Synthesis.

Abstract

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1,3-Dipolar Cycloaddition Reactions of Azomethine Ylides with Carbonyl Dipolarophiles Yielding Oxazolidine Derivatives

“…Azomethine ylides are mostly generated in situ due to their high reactivity and/or transient existence; however, in some cases, stabilized ylides have been isolated [19][20][21]. The most frequent type of 1,3-dipolar cycloaddition reaction of azomethine ylides is that with alkenyl or alkynyl dipolarophiles substituted with electron-withdrawing groups, providing access to pyrrolidine-containing molecules of biological [18,[22][23][24][25][26] or materials science interest [27][28][29][30][31]. The reactions with multiple bonded heteroatom systems such as carbonyl, thiocarbonyl, isothiocyanato, imino, isocyanato, nitrile, nitroso, and azo derivatives are also known, but less well studied [7,16,[32][33][34][35][36][37][38].…”

Formation of a Five‐Membered Ring

“…The reaction of azomethine ylide with alkenes is a powerful method for the synthesis of pyrrolidines, an important building block [38][39][40][41] in the synthesis of natural products and pharmaceuticals. As many reviews [42][43][44][45] and monographs [46][47][48] have been prepared on this subject, only very recent investigations are highlighted in this section.…”

The Synthesis of 9,10‐Dihydro‐9,10‐(Methaniminomethano)Anthracene andN‐Protected Derivatives Via Double Reductive Amination

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An efficient synthesis of 9,10-dihydro-9,10-(methaniminomethano)anthracene and several N-protected derivatives is described via the double reductive amination of cis-9,10-dihydro-9,10-dicarboxaldehyde.In the course of investigations into the generation of 2-azaallyl anions [1,2] via cycloreversions of N-metallated nitrogen-containing heterocycles, [3 -5] we

…”

“…In the course of investigations into the generation of 2-azaallyl anions [1,2] via cycloreversions of N-metallated nitrogen-containing heterocycles, [3 -5] we…”

“…No spectroscopic data have been previously published for this known [6] compound. R f ¼ 0.33 (50% ethyl acetate/ hexanes on neutral alumina, stained with I 2 ); IR (CH 2 Cl 2 ) 3351 (w) cm 21 12-(p-Methoxyphenyl)methyl)-9,10-dihydro-9,10-(methaniminomethano)anthracene (2). p-Methoxybenzylamine (58 mg, 0.42 mmol) and acetic acid (25 mg, 0.42 mmol) were dissolved in CH 2 Cl 2 (4 mL) and cooled to 2788C.…”