Synthesis of Dihydrofurans and Dihydropyrans with Unsaturated Side Chains Based on Ring Size-Selective Ring-Closing Metathesis.

ChemInform ◽  
2007 ◽  
Vol 38 (18) ◽  
Author(s):  
Bernd Schmidt ◽  
Stefan Nave
Keyword(s):  
Side Chains ◽  
Ring Size ◽  
Ring Closing Metathesis

Synthesis of Cembranoid Analogues through Ring-Closing Metathesis of Terpenoid Precursors: A Challenge Regarding Ring-Size Selectivity

2015 ◽  
Vol 21 (35) ◽  
pp. 12396-12404 ◽  
Author(s):  
Tanja Heidt ◽  
Angelika Baro ◽  
Andreas Köhn ◽  
Sabine Laschat
Keyword(s):  
Ring Size ◽  
Size Selectivity ◽  
Ring Closing Metathesis

scholarly journals α-Bromodiazoacetamides – a new class of diazo compounds for catalyst-free, ambient temperature intramolecular C–H insertion reactions

2013 ◽  
Vol 9 ◽  
pp. 1407-1413 ◽  
Author(s):  
Åsmund Kaupang ◽  
Tore Bonge-Hansen
Keyword(s):  
Ambient Temperature ◽  
Diazo Compounds ◽  
Side Chains ◽  
Ring Size ◽  
Insertion Reactions ◽  
Substitution Pattern ◽  
Metal Free ◽  
New Class ◽  
Cyclic Amide ◽  
Thermolysis Reaction

In this work, we introduce a new class of halodiazocarbonyl compounds, α-halodiazoacetamides, which through a metal-free, ambient-temperature thermolysis perform intramolecular C–H insertions to produce α-halo-β-lactams. When carried out with α-bromodiazoacetamides bearing cyclic side chains, the thermolysis reaction affords bicyclic α-halo-β-lactams, in some cases in excellent yields, depending on the ring size and substitution pattern of the cyclic amide side chains.

Ring size effect in McMurry cyclization of 1,ω-di((azulen-1-yl)-carbonyl) alkanes

2020 ◽  
Vol 65 (1) ◽  
pp. 83-88
Author(s):  
Eugenia Andreea DRAGU ◽  
◽  
Alexandru C. RAZUS ◽  
Keyword(s):  
Size Effect ◽  
Ring Size

Influence of Flexible Side-Chains on the Breathing Phase Transition of Pillared Layer MOFs: A Force Field Investigation

2020 ◽  
Author(s):  
Julian Keupp ◽  
Johannes P. Dürholt ◽  
Rochus Schmid
Keyword(s):  
First Principles ◽  
Good Accuracy ◽  
Field Investigation ◽  
Square Lattice ◽  
Side Chain ◽  
Second Step ◽  
Side Chains ◽  
Dynamics Simulations ◽  
Complex Phenomena ◽  
Closed Pore

The prototypical pillared layer MOFs, formed by a square lattice of paddle-<br>wheel units and connected by dinitrogen pillars, can undergo a breathing phase<br>transition by a “wine-rack” type motion of the square lattice. We studied this not<br>yet fully understood behavior using an accurate first principles parameterized force<br>field (MOF-FF) for larger nanocrystallites on the example of Zn 2 (bdc) 2 (dabco) [bdc:<br>benzenedicarboxylate, dabco: (1,4-diazabicyclo[2.2.2]octane)] and found clear indi-<br>cations for an interface between a closed and an open pore phase traveling through<br>the system during the phase transformation [Adv. Theory Simul. 2019, 2, 11]. In<br>conventional simulations in small supercells this mechanism is prevented by periodic<br>boundary conditions (PBC), enforcing a synchronous transformation of the entire<br>crystal. Here, we extend this investigation to pillared layer MOFs with flexible<br>side-chains, attached to the linker. Such functionalized (fu-)MOFs are experimen-<br>tally known to have different properties with the side-chains acting as fixed guest<br>molecules. First, in order to extend the parameterization for such flexible groups,<br>1a new parametrization strategy for MOF-FF had to be developed, using a multi-<br>structure force based fit method. The resulting parametrization for a library of<br>fu-MOFs is then validated with respect to a set of reference systems and shows very<br>good accuracy. In the second step, a series of fu-MOFs with increasing side-chain<br>length is studied with respect to the influence of the side-chains on the breathing<br>behavior. For small supercells in PBC a systematic trend of the closed pore volume<br>with the chain length is observed. However, for a nanocrystallite model a distinct<br>interface between a closed and an open pore phase is visible only for the short chain<br>length, whereas for longer chains the interface broadens and a nearly concerted trans-<br>formation is observed. Only by molecular dynamics simulations using accurate force<br>fields such complex phenomena can be studied on a molecular level.

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