A quantum dual pair \mathfraks\mathfrakl2 ,\mathfrakon \mathfrak{s}\mathfrak{l}_2 ,\mathfrak{o}_n and the associated Capelli identity

A quantum analogue of the dual pair is introduced in terms of the oscillator representation of U _q . Its commutant and the associated identity of Capelli type are discussed.     

Evaluation of Furan Photooxygenation as a Device for Construction of the Zaragozic Acid (Squalestatin) Core

A practical application of the photooxygenation chemistry of 3-substituted furans to construction of the zaragozic acid/squalestatin backbone is described. Although addition of 3-lithiofuran to the tartrate-derived aldehyde 7 proceeds without chelation control to give a 1:1 mixture of diastereomeric alcohols 8, it is demonstrated initially that ready conversion to the polyfunctional intermediate 10 is possible by sequential treatment of 9 with singlet oxygen, sodium borohydride, and triisopropylsilyl triflate. The actual enantiocontrolled route consisted of oxidation of 8 to the ketone and Wittig olefination of the latter in advance of asymmetric dihydroxylation with AD-mix-beta. Once this series of transformations had been accomplished, formation of the target product 30 was realized by an entirely comparable photooxygenation.     

Size-selective formation of C78 fullerene from a three-dimensional polyyne precursor

Multicyclic cagelike cyclophanes 2 a and 2 b containing cyclobutene rings have been prepared as precursors of three-dimensional polyynes C78H18 (1a) and C78H12Cl6 (1b), respectively. Laser irradiation of 2a and 2b induced expulsion of the aromatic fragment, indane, to give the three-dimensional polyyne anions C78H18- and C78H12Cl6-, respectively. Whereas the former anion lost only four hydrogen atoms to form C78H14-, complete loss of all hydrogen and chlorine atoms was observed from the latter anion, to yield a C78- ion that has a fullerene structure which was proven by its characteristic fragmentation pattern.     

Stereodivergent synthesis of 1,4-bifunctional compounds by regio- and diastereoselective Pd-catalyzed allylic substitution reaction

Highly stereoselective synthesis of 1,4-bifunctional compounds was accomplished via 1,2-asymmetric induction to α-oxyaldehyde and α-oxyketone followed by regio- and diastereoselective Pd-catalyzed allylic substitution reaction. We found that trifluoroacetate is a suitable leaving group for the allylic substitution reaction. Various nucleophiles containing carbon, nitrogen, and sulfur can be applied to the method. Both 1,4-syn- and 1,4-anti-adducts were synthesized with high stereoselectivity by using stereodivergent reduction of the propargyl alcohols followed by allylic substitution reaction.     

Highly stereoselective and stereodivergent synthesis of four types of THF cores in acetogenins using a C4-chiral building block

[reaction: see text] Four stereoisomers of the THF cores, synthetic intermediates of acetogenins, have been synthesized with high diastereoselectivity by asymmetric alkynylation and subsequent stereodivergent THF ring formation. The asymmetric alkynylation of alpha-oxyaldehyde with (S)-3-butyne-1,2-diol derivatives (C4-unit) gave good yields of syn and anti adducts with >97:3 dr and 94:6 dr, respectively. These adducts were converted into the four types of THF compounds via one-pot THF formation or via intramolecular Williamson synthesis.     

Systematic construction of a monotetrahydrofuran-ring library in annonaceous acetogenins by asymmetric alkynylation and stereodivergent tetrahydrofuran-ring formation

All eight diastereoisomers of the monotetrahydrofuran-ring cores of annonaceous acetogenins have been synthesized through utilization of asymmetric alkynylation and stereodivergent one-pot tetrahydrofuran-ring formation. In all cases, the asymmetric alkynylation proceeded with very high diastereoselectivity to give eight kinds of optically pure tetrahydrofuran core from a common alpha-oxyaldehyde. We also describe a comparison of the (1)H NMR, (13)C NMR, and CD spectral data of the eight isomers and give full details of the tetrahydrofuran-ring construction including a model study of asymmetric alkynylation.     

Stereocontrolled synthesis and optical properties of all-cis poly(phenylene vinylenes) (PPVs): a method for direct patterning of PPVs

Geometrically pure, all-cis poly(phenylene vinylenes) (PPVs) are synthesized by Suzuki-Miyaura-type polycondensation of 2,5-dioctyloxy-1,4-benzenediboronic acid with (Z,Z)-bis(2-bromoethenyl)benzenes, which are prepared by ruthenium-catalyzed (Z)-selective double hydrosilylation of diethynylbenzenes, followed by bromodesilylation of the resulting (Z,Z)-bis(2-silylethenyl)benzenes with N-bromosuccinimide. The all-cis PPVs thus obtained undergo one-way photoisomerization to the corresponding trans-PPVs both in solution and in the solid. This phenomenon is applied to direct microscale patterning of PPVs onto a quartz substrate.     

Pressure-induced superconductivity in noncentrosymmetric heavy-fermion CeRhSi3

We report the pressure-induced superconductivity in the noncentrosymmetric heavy-fermion CeRhSi3. The superconductivity emerges above about 12 kbar even though the antiferromagnetic ordering persists. Furthermore, another anomaly is observed in the superconducting phase. The anomalous magnetic field-temperature phase diagram with a high upper critical field suggests that an unconventional superconductivity is realized in CeRhSi3.