The total synthesis of lundurines A-C has been accomplished in racemic and enantiopure forms in 11-13 and 12-14 steps, respectively, without protection/deprotection of functional groups, by a novel tandem double condensation/Claisen rearrangement, a gold(I)-catalyzed alkyne hydroarylation, a cyclopropanation via formal [3 + 2] cycloaddition/nitrogen extrusion, and a remarkable olefin migration ...

A straightforward and unified strategy to access Amaryllidaceae alkaloids comprising a cis-3a-aryloctahydroindole scaffold has been developed. The strategy features Eschenmoser-Claisen rearrangement of allylalcohol as a key step for the installation of all-carbon quaternary stereocenters present in these alkaloids. The consequent iodolactonization-reduction-oxidation sequence beautifully assemb...

An efficient synthetic approach to the core structure of the manzamine alkaloids is reported, particularly in relation to incorporating a one-carbon unit in ring B from which the aldehyde in ircinal A or the beta-carboline unit in manzamine A could potentially be generated. The key steps involve a Johnson-Claisen rearrangement, enolate alkylation, dithiane alkylation and a stereoselective intra...

A highly stereocontrolled, convergent total synthesis of kendomycin [(-)-TAN2162], an ansa-macrocyclic antibiotic, is reported. The key of the strategy is an unprecedented Tsuji-Trost macrocyclic etherification, followed by a transannular Claisen rearrangement to construct the 18-membered carbocyclic framework. The oxa-six- and five-membered rings were also stereoselectively constructed respect...

The asymmetric formal synthesis of schulzeines A and C is described. Key features of the synthesis include the efficient and stereoselective construction of the benzoquinolizidine skeleton via the aza-Claisen rearrangement-induced ring expansion of the 1-vinyl-N-glycyl-isoquinoline, which was prepared by the highly enantioselective asymmetric allylation of the 8-benzyloxy-substituted dihydroiso...

Carroll rearrangement of b-keto esters derived from tertiary allylic alcohols, for example, 7, under basic conditions followed by decarboxylation of the resulting b-keto acids yielded the expected c,d-unsaturated methyl ketones 8 with a range of olefin geometries from 100:0 to 1:1.8 E=Z, depending on the relative steric requirements of the two groups at the allylic center. 2003 Elsevier Ltd. Al...

The enantioselective total synthesis of callipeltoside A is described. Two syntheses of the macrolactone subunit are included: the first relies upon an Ireland-Claisen rearrangement to generate the trisubstituted olefin geometry and the second utilizes an enantioselective vinylogous aldol reaction for this purpose. Enantioselective syntheses of the sugar and chlorocyclopropane side chain fragme...

Asymmetric syntheses of both 1-deoxy-6,8a-di-epi-castanospermine and 1-deoxy-6-epi-castanospermine, polyhydroxylated indolizidine alkaloids that act as selective glycosidase inhibitors, have been accomplished in seven steps. The key feature of our unique syntheses includes the stereoselective introduction of the C-3 and C-4 hydroxyl groups utilizing the aza-Claisen rearrangement-induced ring ex...