نتایج جستجو برای: diene
تعداد نتایج: 3081 فیلتر نتایج به سال:
In situ resolution of the rapidly racemising diphosphine BIPHEP and its relatives with the cationic Rh complex of (S,S)-bicyclonona-2,6-diene permits the asymmetric hydrogenation of dehydroamino esters.
A new and efficient method for the preparation of highly enantiomerically enriched α-aryl 2- or 3-indolyl-methanamines by rhodium-catalyzed asymmetric arylation of N-sulfonyl indolylimines with arylboronic acids using chiral bicyclo[3.3.0] diene was developed.
The exomethylenes of 2,6-disubstituted bicyclo[3.3.1]nonan-9-ones 2 are readily isomerized over a palladium catalyst under an atmosphere of hydrogen to predominantly form the isomer 3 with C2 symmetry with very little formation of the analogous product with C(s) symmetry. A hydrogen source is essential to effect the rearrangement.
We prove that a class of one-loop partition functions found by Dienes, giving rise to a vanishing cosmological constant to one-loop, cannot be realized by a consistent lattice string. The construction of non-supersymmetric string with a vanishing cosmological constant therefore remains as elusive as ever. We also discuss a new test that any one-loop partition function for a lattice string must ...
3A5AF, a biomass derived furan obtained from chitin, is used as diene in the Diels–Alder reaction with maleimides. This allows incorporation of bio-based nitrogen into final products, challenge unmet by commonly furanics.
Inverse electron demand Diels-Alder reaction of functionalized 5,5'-bi-1,2,4- triazines with bicyclo[2.2.1]hepta-2,5-diene in boiling p-cymene leads to a range of 6,6'- disubstituted-2,2'-bipyridines in good yield.
C(72)-Macrocyclic systems functionalized with nitroaryl and arylamino groups were synthesized from the bisdioxine diacid dichloride 1,3,5,7-tetra-tert-butyl-2,6,9-trioxabicyclo[3.3.1]nona-3,7-diene-4,8-dicarbonyl dichloride (3).
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