441352-34-7Relevant academic research and scientific papers
The effect of electrostatic interactions on conformational equilibria of multiply substituted tetrahydropyran oxocarbenium ions
Yang, Michael T.,Woerpel
supporting information; experimental part, p. 545 - 553 (2009/06/18)
The three-dimensional structures of dioxocarbenium ions related to glycosyl cations were determined by an analysis of spectroscopic, computational, and reactivity data. Hypothetical low-energy structures of the dioxocarbenium ions were correlated with both experimentally determined 1H NMR coupling constants and diastereoselectivity results from nucleophilic substitution reactions. This method confirmed the pseudoaxial preference of C-3 alkoxy-substituted systems and revealed the conformational preference of the C-5 alkoxymethyl group. Although the monosubstituted C-5 alkoxymethyl substituent preferred a pseudoequatorial orientation, the C-5-C-6 bond rotation was controlled by an electrostatic effect. The preferred diaxial conformer of the trans-4, 5-disubstituted tetrahydropyranyl system underscored the importance of electrostatic effects in dictating conformational equilibria. In the 2-deoxymannose system, although steric effects influenced the orientation of the C-5 alkoxymethyl substituent, the all-axial conformer was favored because of electrostatic stabilization.
A general strategy for the convergent synthesis of fused polycyclic ethers via B-alkyl Suzuki coupling: Synthesis of the ABCD ring fragment of ciguatoxins
Sasaki, Makoto,Ishikawa, Makoto,Fuwa, Haruhiko,Tachibana, Kazuo
, p. 1889 - 1911 (2007/10/03)
A new method for convergent coupling of fused polycyclic ethers has been developed, which relies on B-alkyl Suzuki crosscoupling of lactone-derived enol triflates or phosphates. The strategy was successfully applied to a convergent synthesis of the ABCD r
