Incorporation of an allene unit into 1,4-dihydronaphthalene: generation of 1,2-benzo-1,4,5-cycloheptatriene and its dimerization

Substituent effects on the ring-opening mechanism ofgem-dibromospiropentanes to related allenes: a theoretical study

“…It can easily be understood that removing of the bromine anion from 5a led to changing their characters from nucleophilic to electrophilic in accordance with previous studies. In this case, carbenoids as well as silylenoids can act as either nucleophiles or electrophiles …”

“…). It is clear that the ring opening to allene may also occur starting from free carbene . Then, free carbenes ( 8a , 8b , 8c , 8d , 8e , 8f , 8g , 8h , 8i , 8j ) have been considered as either singlet or triplet for the ring‐opening reaction mechanisms of the title structures.…”

“…In this case, carbenoids as well as silylenoids can act as either nucleophiles or electrophiles. [14][15][16]31,32] The molecular electrostatic potential (MEP) is most favored reactivity map to display the regions on organic molecules for the electrophilic and nucleophilic attacks. To determine reactive sites for electrophilic and nucleophilic attacks as well as hydrogen-bonding interactions for the title compound, the molecular electrostatic map (MEP) was performed at the B3LYP/6-31G(d) level of theory.…”

“…This method, so-called DMS reaction, is well documented in the literature. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] Interestingly, lowering the reaction temperature to À55°C leads to the formation of either cyclobutenes 3 (Route 2) or the compounds of 4 (Route 3) depending on the substituents of the spiropentane rings (Scheme 1). Although the synthetic and mechanistic aspects of the carbocationic skeletal rearrangements (Route 2 and 3) were investigated in detail many times by Zefirov et al, [10] no theoretical calculations about the conversions of lithium halogenospiropentanoids into the corresponding allenes and the substituent effects on this rearrangement have been reported so far (Route 1).…”

Synthesis, Metal Ion Complexation and Computational Studies of Thio Oxocrown Ethers

“…Quantum-mechanical calculations were carried out on initially geometry optimized structures at the DFT level using the Gaussian03 suite of programs [36]. The DFT methods are effective for the theoretical studies of supramolecular structures [37,38,39]. The B3LYP, a version of the DFT method, which uses Becke’s three-parameter functional (B3) [40] and includes a mixture of HF and DFT exchange terms associated with the gradient corrected correlation functional of Lee, Yang, and Parr (LYP) [41].…”