A complete stereocontrol of 1,3-dipolar cycloaddition of N-metalated azomethine ylides onto endohedral fullerene H2@C60 is reported for the first time. The stereodivergent synthesis of either the cis or the trans endohedral cycloadduct is achieved with excellent diastereo- and enantioselectivities.

Starting from enantiomeric pure 1-[(3S,5R)- and 1-[(3R,5S)-3-(hydroxymethyl)-2-methylisoxazolidin-5-yl]-5-methylpyrimidine-2,4(1H,3H)-diones (-)7a and (+)7b, obtained by lipase-catalyzed resolution, pure diethyl{[(3S,5R)-2-methyl-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)isoxazolidin-3-yl]methyl}phosphonate (-)12a and diethyl{[(3R,5S)-2-methyl-5-(5-methyl-2,4-dioxo-3,4-dihydropyrimidi...

U d o E n g e l h a r d t * u n d T h o m a s B ü n g e r Institut für Anorganische Chemie der Freien Universität Berlin, Fabeckstraße 34-36, D-1000 Berlin 33 Z. Naturforsch. 84b , 1107-1111 (1979); eingegangen a m 30. März /18 . Mai 1979 Tetraalkyl-dichloro-disiloxanes, N M R , I R , R a m a n Phenoxy-thiophosphoryl -d ihydrazide C 6 H 5 O P ( S ) ( N H N H 2 ) 2 ( la) and phenoxy-phos phoryl-...

Oligonucleotides containing 7-bromo-7-deaza-2,8-diaza-2 0-deoxyadenosine (3) and 5-amino-3-bromo-4-carbamoyl-1-(2 0deoxy-b-D-erythro-pentofuranosyl)pyrazole (4) were synthesized. Compound 3 was prepared from 7-bromo-8-aza-7-deaza-2 0-deoxyadenosine (5) via the 1,N-etheno derivative 6 and was converted into the phosphoramidite 11. The 7-bromo substituent of 3 increases oligonucleotide duplex sta...

Treatment of cyanuric chloride with chiral amines or esters of chiral amino acids gave chiral 2,4-dichloro-6-alkylamino-1,3,5-triazines (2-5) in 49-69% yield, which were found useful as coupling reagents. Enantioselective activation and enantioselective aminolysis in the presence of 2-5 was observed.

BACKGROUND AND OBJECTIVE The junctional epithelium attaches to the enamel surface with hemidesmosomes (of which laminin-5 and integrin-alpha(6)beta(4) are the main components) in the internal basal lamina. Laminin-5 is also involved in cell motility with integrin-alpha(3)beta(1), although their functions have not yet been clarified.The purpose of this study was to determine the functions of tho...

Catalytic asymmetric 1,3-dipolar cycloadditions of azomethine ylides have turned out to be one of the most efficient methods for the preparation of enantioenriched pyrrolidines. The past decade has witnessed the development of a bunch of well-defined catalytic systems capable of affording excellent diastereo and enantioselectivities. Recently, a great effort has been focused on expanding the sc...

We have developed a highly efficient procedure for carrying out the catalytic enantioselective (3+2) cycloaddition between enals and stable azomethine ylides such as isoquinolinium and phthalizinium methylides. Under the optimized reaction conditions highly substituted chiral pyrroloisoquinolines and pyrrolophthalazines have been obtained in high yields and excellent diastereo- and enantioselec...

Chiral complexes formed by phosphoramidites such as (Sa,R,R)-9 and Cu(OTf)2 are excellent catalysts for the general 1,3-dipolar cycloaddition between azomethine ylides and nitroalkenes affording the corresponding tetrasubstituted proline esters mainly as exo-cycloadducts in high er at room temperature. The exo-cycloadducts can be obtained in enantiomerically pure form just after simple recrysta...

In the mol-ecule of the title compound, C(20)H(16)Cl(2)N(2)O(2), the planar benzimidazole ring system is oriented with respect to the furan and dichloro-benzene rings at dihedral angles of 53.39 (6) and 31.04 (5)°, respectively. In the crystal structure, inter-molecular C-H⋯Cl hydrogen bonds link the mol-ecules into centrosymmetric R(2) (2)(8) dimers. These dimers are connected via a C-H⋯π cont...