Systems Overman rearrangement

Overman and coworkers synthesized the ABC core (177) by a stereoselective intramolecular Maimich reaction from tra s-2,3-dialkylated cyclohexanone (180), which was prepared from D-(-)-quinic acid [95] (Scheme 15). The ABC ring system was constructed by ene-amide formation. The ene-amide (178) was converted to 177 by successive epoxidation, add-rearrangement, and ehmination. 

Overman and co-workers continue to report new applications of their tandem cationic aza-Cope rearrangement-Mannich cyclization route to nitrogen heterocyclic systems. Perhaps the nicest illus-... 

In 1993, Overman achieved the first enantioselective total synthesis of (—)-strychnine using the optically pure monoacetate (+)-36, which was prepared by the enzymatic hydrolysis of 35 (70,71), as a starting material (Scheme 5). The key reaction in this synthesis is the cationic aza-Cope-Mannich rearrangement, which was previously developed by Overman et al. for the syntheses of various alkaloids, such as akuammicine (72-76), to assemble the CDE core ring system. The... 

Ito T, Overman LE, Wang J. Enantioselective synthesis of angularly substituted 1-azabicyclic ring systems dynamic kinetic resolution using aza-Cope rearrangements. J. Am. Chem. Soc. 2010 132(10) 3272-3273. 

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