Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties

• Liliia Moshniaha,
• Marika Żyła-Karwowska,
• Joanna Cybińska,
• Piotr J. Chmielewski,
• Ludovic Favereau and
• Marcin Stępień

Beilstein J. Org. Chem. 2020, 16, 895–903, doi:10.3762/bjoc.16.81

• , which predict inversion barriers ΔG‡,298 of 20.0 and 24.7 kcal/mol for models of cNDA3O and cNMI3H, respectively (Supporting Information File 1, Figures S31 and S32). The latter value is consistent with the observed greatest stability of cNMI3H. Frontier molecular orbitals of the boomerangs reveal

Synthesis of dinucleoside acylphosphonites by phosphonodiamidite chemistry and investigation of phosphorus epimerization

• William H. Hersh

Beilstein J. Org. Chem. 2015, 11, 184–191, doi:10.3762/bjoc.11.19

• differences in rates of diastereomer decomposition. Calculation of acylphosphonite inversion barrier. As described in the Introduction, inversion barriers for phosphines, acylphosphines, and phosphites are known. These were calculated first for validation of the method. The structures of chiral phosphine 18

• on the conformations about the P–O bonds, the energies are comparable (separated by less than 1 kcal/mol) and do not have a significant impact on the inversion barriers. Transition states were located using routines implemented in Gaussian (see Supporting Information File 1 for details), and in all

• –C1–O 120.23(8), P–C1–C2 119.78(8), C2–C1–O 119.82(9). Synthesis of a dinucleoside acylphosphonate (3b) and a formate diester (1a). Reaction of an H-phosphonodiamidite with acid chlorides. Synthesis of dinucleosides. Calculated phosphine, acylphosphine, phosphite, and acylphosphonite inversion

Dimerisation, rhodium complex formation and rearrangements of N-heterocyclic carbenes of indazoles

• Zong Guan,
• Jan C. Namyslo,
• Martin H. H. Drafz,
• Martin Nieger and
• Andreas Schmidt

Beilstein J. Org. Chem. 2014, 10, 832–840, doi:10.3762/bjoc.10.79

• to be true minima by the absence of imaginary frequencies or transition states by the occurrence of one negative frequency. Plots were obtained using Maestro 9.1.207, the graphical interface of Jaguar. Inversion barriers have been calculated fully relaxed, fixating one torsion angle around the

Structure of 1,5-benzodiazepinones in the solid state and in solution: Effect of the fluorination in the six-membered ring

• Marta Pérez-Torralba,
• Rosa M. Claramunt,
• M. Ángeles García,
• Concepción López,
• M. Carmen Torralba,
• M. Rosario Torres,
• Ibon Alkorta and
• José Elguero

Beilstein J. Org. Chem. 2013, 9, 2156–2167, doi:10.3762/bjoc.9.253

• studies at the B3LYP/6-311++G(d,p) level were carried out on these compounds and on four non-fluorinated derivatives, allowing to calculate geometries, tautomeric energies and ring-inversion barriers, that were compared with the experimental results obtained by static and dynamic NMR in solution and in

• solid state. Keywords: benzodiazepinones; DFT; GIAO calculations; inversion barriers; multinuclear NMR; tautomerism; X-ray structures; Introduction In our previous paper [1] we already reported the relevance of 1,5-benzodiazepine derivatives in central nervous system pathologies as well as for other

• experimental inversion barriers of 3a, 5a (twice) and 6a have been determined and are given in Table 4. We have calculated those of 1a and 2a. The barriers for an AB system that become an A2 one depend on three values: i) the coalescence temperature TC; ii) the difference in Hz of the protons of the AB system