Total Synthesis of the Natural Carbazoles Murrayanine and Murrayafoline A, Based on the Regioselective Diels?Alder Addition of exo-2-Oxazolidinone Dienes.

Abstract

Dienes. -Key step to a novel synthesis of natural carbazoles murrayanine (VII) and murrayafoline A (IX) is the preparation of carbaldehyde (III) via highly regioselective BF3-catalyzed Diels-Alder reaction. -(BENAVIDES, A.; PERALTA, J.; DELGADO, F.; TAMARIZ*,

Highly Regio- and Stereoselective Diels-Alder Cycloadditions via Two-Step and Multicomponent Reactions Promoted by Infrared Irradiation under Solvent-Free Conditions

“…The latter have proved to be stable, and they undergo Diels-Alder cycloadditions with high selectivity [ 16 – 20 ]. In addition, they have shown to be useful synthons in the preparation of carbazoles [ 21 – 24 ], and in the synthesis of new polycyclic compounds by a cascade [4 + 2] cycloaddition/cyclopentannulation/1,5-sigmatropic rearrangement process with Fischer (arylalkynyl)(alkoxy)carbenes [ 25 ]. Moreover, dienes 1 – 3 have been employed to synthesize new η 4 -diene-Fe(CO) 3 complexes, which undergo the addition of alkyllithium reagents to produce stable and unprecedented conjugated enamine-enol ester- and enamido-enol-Fe(CO) 3 complexes [ 26 ].…”