A General Approach to Optically Pure [5]-, [6]-, and [7]Heterohelicenes
作者:Jaroslav Žádný、Andrej Jančařík、Angelina Andronova、Michal Šámal、Jana Vacek Chocholoušová、Jaroslav Vacek、Radek Pohl、David Šaman、Ivana Císařová、Irena G. Stará、Ivo Starý
DOI:10.1002/anie.201108307
日期:2012.6.11
Spiral staircases: A general method for the preparation of opticallypure [5]‐, [6]‐, and [7]heterohelicenes is based on a CoI‐ or Ni0‐catalyzed diastereoselective [2+2+2] cycloisomerization of centrally chiral triynes to deliver helicenes comprising two 2H‐pyran rings. The configuration, which can be predicted, does not depend on helicene length or functional groups present.
Synthesis of Long Oxahelicenes by Polycyclization in a Flow Reactor
作者:Jindřich Nejedlý、Michal Šámal、Jiří Rybáček、Miroslava Tobrmanová、Florence Szydlo、Christophe Coudret、Maria Neumeier、Jaroslav Vacek、Jana Vacek Chocholoušová、Miloš Buděšínský、David Šaman、Lucie Bednárová、Ladislav Sieger、Irena G. Stará、Ivo Starý
DOI:10.1002/anie.201700341
日期:2017.5.15
series of oxahelicenes composed of ortho/meta‐annulated benzene/pyridine and 2H‐pyran rings were synthesized on the basis of the cobalt(I)‐mediated (or rhodium(I)‐ or nickel(0)‐mediated) double, triple, or quadruple [2+2+2] cycloisomerization of branched aromatic hexa‐, nona‐, or dodecaynes, thus allowing the construction of 6, 9, or 12 rings in a single operation. The use of a flowreactor was found
On the Origin of Diastereoselectivity in [2 + 2 + 2] Cycloisomerization of Chiral Triynes: Controlling Helicity of Helicene-like Compounds by Thermodynamic Factors
作者:Petr Sehnal、Zuzana Krausová、Filip Teplý、Irena G. Stará、Ivo Starý、Lubomír Rulíšek、David Šaman、Ivana Císařová
DOI:10.1021/jo701997p
日期:2008.3.1
selected helicene-like compounds were measured indicating their lower configurational stability in comparison to the parent carbohelicenes. Free energy differences between corresponding pairs of diastereomers (calculated at the DFT B3LYP/TZV+P level) were in excellent agreement with the experimental data and allowed for the prediction of the stereochemicaloutcome of the reaction. An optically pure hexacyclic
Synthesis of Methoxy Substituted Centrally Chiral Triynes as Precursors of Functionalised Nonracemic Helicene-Like Compounds
作者:Zuzana Krausová、Petr Sehnal、Filip Teplý、Irena G. Stará、Ivo Starý、David Šaman、Josef Cvačka、Pavel Fiedler
DOI:10.1135/cccc20071499
日期:——
A modular synthesis of a series of methoxy substituted optically pure aromatic triynes (-)-(S)-5-9 and (-)-(R)-10 is presented. It relies on key operations such as substitution of benzylic bromine with an alkoxy group and aryl-alkyne coupling reaction to combine appropriate methoxy substituted benzene/naphthalene building blocks and chiral alkynol synthons such as (-)-(2S)-but-3-yn-2-ol and (-)-(1R)-1-phenylprop-2-yn-1-ol. The triyne molecules comprise a diphenylacetylene, 1-(phenylethynyl)naphthalene or 1,1'-ethyne-1,2-diyldinaphthalene core unit. They are intended to serve as [2+2+2] cyclisation precursors of methoxy substituted nonracemic helicene-like compounds with a penta-, hexa- and heptacyclic helical scaffold.