An approach to the skeleton of the securinega alkaloids. The total synthesis of (+/-)-securinine

[structure: see text]. The concise total synthesis of securinine in nine steps from readily available starting materials is described. Key steps of the synthesis include an addition of a silyloxyfuran to an in situ generated iminium ion and a novel ring closing metathesis reaction.     

A facile approach to the synthesis of securinega alkaloids: stereoselective total synthesis of (−)-allonorsecurinine

A concise stereoselective total synthesis of alkaloid (−)-allonorsecurinine is described utilizing classical reactions such as Grignard, Aldol and Horner-Wittig reactions as the key steps.     

An aldol approach to the enantioselective synthesis of (-)-oseltamivir phosphate

A formal asymmetric synthesis of the antiviral agent (-)-oseltamivir phosphate is achieved using two aldol reactions as key steps.     

First enantioselective total synthesis of (-)-tejedine

[structure: see text] The first enantioselective total synthesis of (-)-tejedine (1) is reported. Tejedine is a seco-bisbenzyltetrahydroisoquinoline isolated in 1998 as a minor component from Berberis vulgaris. The synthesis was achieved using a strategy employing four key steps, including a chiral auxiliary-assisted diastereoselective Bischler-Napieralski cyclization.     

First enantioselective total synthesis of (-)-Centrolobine

[structure: see text] The first enantioselective total synthesis of (-)-Centrolobine is described. The key reaction is the synthesis of the cis-disubstituted tetrahydropyran framework by intramolecular cyclization of the enantiopure hydroxyketone 3 with Et3SiH and TMSOTf. The stereoselective reduction of the beta-ketosulfoxide 4 is the source of chirality. Revision of the absolute configuration of (-)-Centrolobine is proposed.     

An intramolecular Diels-Alder approach to the eunicelins: enantioselective total synthesis of ophirin B

The enantioselective synthesis of the eunicellin ophirin B has been completed. A ring-closing metathesis provides efficient access to the oxonene ring, and a highly diastereoselective intramolecular Diels-Alder reaction results in the formation of the hydrobenzofuran portion of the molecule.     

Concise, enantioselective total synthesis of (-)-alstonerine

A novel enantioselective total synthesis of (-)-alstonerine has been completed that requires only 15 steps from L-tryptophan. The synthesis features the first application of a Pauson-Khand reaction to synthesize an azabridged bicyclic skeleton. [reaction: see text]     

A catalytic enantioselective total synthesis of (-)-wodeshiol

[formula: see text] (-)-Wodeshiol of > 99% ee has been synthesized from the alpha,beta-enone shown using a number of noteworthy steps including a novel C-C coupling reaction.     

An enantioselective formal synthesis of (-)-thujopsene

Dihydromayurone (3), a key intermediate to synthesize (-)-thujopsene (1), was efficient enantiocontrolled synthesized from ( )-dihydrocarvone through 9 steps in an overall yield of 19.3%. The key step was the Simmons-Smith reaction.     

An enantioselective formal synthesis of （-）-thujopsene

Dihydromayurone （3）, a key intermediate to synthesize （-）-thujopsene （1）, was efficient enantiocontrolled synthesized from （＋）-dihydrocarvone through 9 steps in an overall yield of 19.3%. The key step was the Simmons-Smith reaction.     

A de novo enantioselective total synthesis of (-)-laulimalide

An enantioselective total synthesis of the naturally occurring anticancer agent (-)-laulimalide is described. The synthesis is characterized by extensive use of new reaction methodologies based on catalytic asymmetric acyl halide-aldehyde cyclocondensation (AAC) reactions and transformations of the derived enantioenriched beta-lactones. The synthesis also incorporates a unique allenylstannane glycal acetate alkylation and chemoselective ring-closing metathesis reaction.     

First enantioselective total synthesis of (S)-(−)-longianone

An efficient stereoselective synthesis of (S)-(?)-longianone was achieved from sugar derived 1,2-cyclopropanecarboxylate involving bromonium ion mediated solvolytic ring opening and a one-pot dehydrohalogenation, stereoselective intramolecular hetero Michael addition (IHMA) and ester hydrolysis as key steps.     

Pd-catalyzed enantioselective aerobic oxidation of secondary alcohols: applications to the total synthesis of alkaloids

Enantioselective syntheses of the alkaloids (-)-aurantioclavine, (+)-amurensinine, (-)-lobeline, and (-)- and (+)-sedamine are described. The syntheses demonstrate the effectiveness of the Pd-catalyzed asymmetric oxidation of secondary alcohols in diverse contexts and the ability of this methodology to set the absolute configuration of multiple stereocenters in a single operation. The utility of an aryne C-C insertion reaction in accessing complex polycyclic frameworks is also described.     

An organo-catalytic approach to the enantioselective synthesis of (R)-selegiline

An efficient enantioselective synthesis of (R)-selegiline has been achieved by two routes, via proline-catalyzed α-aminooxylation as well as α-amination of phenylpropanaldehyde as the key step.     

A concise and enantioselective approach to the total synthesis of (−)-lasubine I

An efficient, enantioselective total synthesis of (−)-lasubine I (1) has been achieved in an overall 8.8% yield from readily available starting materials. The important features of this approach include the creation of stereogenic centers through two sequential highly stereoselective Roush allylborations and the use of S_N2 cyclization and ring-closing metathesis reactions for the construction of the quinolizidine skeleton.     

An enantioselective total synthesis of (+)- and (-)-saudin. Determination of the absolute configuration.

A short efficient enantioselective synthesis of both (+)- and (-)-saudin, a naturally occurring hypoglycemic diterpene, is described. This synthesis establishes the absolute configuration of natural (-)-saudin for the first time. The key steps include the enantioselective construction of a dimethyl Hagemann's ester by an asymmetric Michael reaction and establishment of the key 1,3 disposed quaternary centers by means of a novel Ti(IV) promoted Claisen rearrangement. The assembly of the polycyclic ketal skeleton was likely under kinetic control proceeding via formation of the C1oxygen-C7 bond through an oxonium ion intermediate in the final stage.