Synthesis of Chromen[4,3-b]pyrrolidines by Intramolecular 1,3-Dipolar Cycloadditions of Azomethine Ylides: An Experimental and Computational Assessment of the Origin of Stereocontrol

Azomethine ylides, generated from imine-derived O-cinnamyl or O-crotonyl salicylaldeyde and α-amino acids, undergo intramolecular 1,3-dipolar cycloaddition, leading to chromene[4,3-b]pyrrolidines. Two reaction conditions are used: (a) microwave-assisted heating (200 W, 185 °C) of a neat mixture of reagents, and (b) conventional heating (170 °C) in PEG-400 as solvent. In both cases, a mixture of two epimers at the α-position of the nitrogen atom in the pyrrolidine nucleus was formed through the less energetic endo-approach (B/C ring fusion). In many cases, the formation of the stereoisomer bearing a trans-arrangement into the B/C ring fusion was observed in high proportions. Comprehensive computational and kinetic simulation studies are detailed. An analysis of the stability of transient 1,3-dipoles, followed by an assessment of the intramolecular pathways and kinetics are also reported.

C. Sallusti Crispi Historiarum reliquiae.

V.I. Prolegomena. V.II. Fragmenta, argumentis commentariis apparatu critico instructa. Accedunt indices.

C. Suetonii Tranquilli Opera;

Mode of access: Internet.

Opera cum Historiarum fragmentis, duabus epistolis ad C. Caesarem et Declamationibus ...

Mode of access: Internet.

C. Crispi Sallustii quae extant; cum notis integris Glareani, Rivii, Ciacconii, Grunteri, Carrionis, Manutii, Putschii, Dousae.

Mode of access: Internet.

Dissertationes in C. Julii Caesaris Commentarios.

Bd. 24. De elegantia Caesaris sive de commentariorum de b. G. et de b. c. differentiis animadversiones / O. Dernoscheck, 1903--Der Zug des Cimbern und Teutonen / A. Helbling, 1898--Unsere Armeesprache im Dienste der Caesar-Übersetzung / M. Hodermann, 1903--Cäsar, der Eroberer Galliens / R. Lange, 1896--Divico oder die von Caesar den Ost-Galliern und Süd-Germanen gegenüber Vertretene Politik, Lfg. I-III / H. von Müllinen, 1898-1901--Die Unterwerfung Galliens durch Cäsar verglichen mit der Bezwingung Frankreichs durch die deutsche Armee im Feldzuge 1870/71 / A. von Oertzen, 1904.

C. Sallusti Crispi Coniuratio Catilinae.

Mode of access: Internet.

Studia critica in C. Lucilium poetam.

Mode of access: Internet.

C. Velleii Paterculi quae supersunt ex Historiae romanae libris duobus ... /

Mode of access: Internet.

Apocolocyntosin denuo recensitam et annotatione illustratam submittit L.C.E. Schusler.

[Inaug.-diss.]

C. Sallustius Crispus, primus in historia, seu Bellum Catilinarium et Jugurthinum,

Mode of access: Internet.

C. Crispi Sallustii de Catilinae conjuratione belloque Jugurthino Historiae : Animadversionibus illustravit Carolus Anthon ...

Lecturis S. P. D. Carolus Anthon. - Bellum Catilinarium. - Bellum Jugurthinum. - Life and writings of Sallust. - Explanatory notes.

Opera. Cum historiarum fragmentis, duabus epistolis ad C. Caesarem, et declamationibus, una in Ciceronem, in Sallustium.

Mode of access: Internet.

C.C. Sallustio

Mode of access: Internet.

C. Sallustii Crispi Bellum Catilinarium, et Jugurthinum, : Ad ultimam Wassii editionem diligenter castigata, : cum commentariis Johannis Min-ellii.

Includes indexes: [27] p. at end.