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The first regioselective, enantioselectiveconjugate addition ofthiols to acyclic α,β,γ,δ-unsaturated dienonesat the δ carbon is described. The reaction, catalyzed by a chiraliron(III)-salen complex derived from cis-2,5-diaminobicyclo[2.2.2]octaneas the scaffold, provides δ-thia-α,β-unsaturatedketones in high yield and enantioselectivity. The bicyclooctane scaffoldof (2R,3R,5R,6R) configuration affords a δ-thia-α,β-unsaturatedketone of (R) configuration, indicating that thesulfur nucleophile is introduced at the siface ofthe γ,δ-double bond. A model providing an explanationfor this regio- and stereoselection is proposed. [ABSTRACT FROM AUTHOR]

A new C2symmetric salen scaffold based on cis-2,5-diaminobicyclo[2.2.2]octane has been synthesized that forms complexes with a wide range of metals. The chromium(III) complex is shown to catalyze the hetero-Diels−Alder reaction and the Nozaki−Hiyama−Kishi reaction with high efficiency and excellent stereoselectivity. [ABSTRACT FROM AUTHOR]

Conjugate reduction of an enone accompanied by in situ intramolecular aldol condensation was used to construct the tetrasubstituted cyclohexane nucleus of phomactins. Subsequent relay ring-closing metathesis completed the nine-membered ansa bridge of the diterpenoid framework. [ABSTRACT FROM AUTHOR]

Stereodefined trisubstituted cyclopropanes bearing naphthyloxy, thiophenyl, and (N-methylamino)methyl groups were synthesized in enantiopure form employing asymmetric cyclopropanation of (E)- and (Z)-allylic alcohols as the key step. In vitro assays of the synthesized cyclopropanes revealed that the Kiof one of the enantiomers as a dual inhibitor of serotonin and norepinephrine transporters is in the low nanomolar range and is comparable to that of duloxetine. [ABSTRACT FROM AUTHOR]

A portion of the macrocyclic cembrenoid diterpene providencin possessing conjoined cyclobutane and furancarboxylate units was synthesized from d-glucose using deoxygenative ring contraction methodology to construct the tetrasubstituted cyclobutane and a Knoevenagel condensation of glyceraldehyde to fabricate the trisubstituted furan. [ABSTRACT FROM AUTHOR]

Condensation of an orsellinate anion with a 2-cyclohexenone (Staunton−Weinreb annulation) afforded a linear tetracycle which was converted to a protected derivative of 12a-epipillaromycinone. Methodology for introducing a 12a-hydroxyl substituent into the tetracycle with correct ( R) configuration is described. [ABSTRACT FROM AUTHOR]

Asymmetric total syntheses of solandelactones E and F confirmed that hydroxyl configuration at C11 in these oxylipins had been misassigned and that the stereochemistry at this center should be reversed. Key steps in the synthesis involved a Nagao asymmetric acetate aldol reaction, a directed Simmons−Smith cyclopropanation, a Holmes−Claisen rearrangement to establish the unsaturated octalactone, and a Nozaki−Hiyama−Kishi coupling to connect two major fragments at C11−C12. [ABSTRACT FROM AUTHOR]