The thermal and Lewis acid (LA) catalyzed cyclizations of quinone 1 involved in the synthesis of Colombiasin A and Elipsaterosin B have been theoretically studied using DFT methods at the B3LYP/6-311G(d,p) computational level. B3LYP calculations suggest that the formal endo [4 + 2] cycloadduct allowing the synthesis of Colombiasin A is preferentially formed under thermal conditions, while in th...

We combine a maximum principle for vector-valued mappings established by D’Ottavio, Leonetti and Musciano [DLM] with regularity results from [BF3] and prove the Hölder continuity of the first derivatives for local minimizers u: Ω → RN of splitting-type variational integrals provided Ω is a domain in R2. Roughly speaking, anisotropic variational integrals ∫ Ω F (∇u) dx with integrand F (∇u) of (...

The intramolecular Diels-Alder reactions of cycloalkenones and terminal dienes occur with high endo stereoselectivity, both thermally and under Lewis-acidic conditions. Through computations, we show that steric repulsion and tether conformation govern the selectivity of the reaction, and incorporation of either BF3 or α-halogenation increases the rate of cycloaddition. With a longer tether, iso...

We consider local minimizers u: R2 ⊃ Ω → RN of variational integrals like ∫ Ω[(1+ |∂1u|)+(1+ |∂2u|)] dx or its degenerate variant ∫ Ω[|∂1u|+ |∂2u|] dx with exponents 2 ≤ p < q < ∞ which do not fall in the category studied in [BF2]. We prove interior C1,αrespectively C1-regularity of u under the condition that q < 2p. For decomposable variational integrals of arbitrary order a similar result is ...

in the present work, impact of lewis acid (la) catalysts bf3, bcl3, and bbr3 on the kinetics andregioselectivity of 1,3-dipolar cycloaddition (1,3-dc) reaction between azidobenzene and acroleinwas theoretically studied using b3lyp/6-31g* level. our results indicate while the uncatalyzed 1,3-dc reaction under investigation takes place via a non-polar, non-regioselective, and lowasynchronous proc...

In this research we used Heavy Propylene Tetramer (HPT) and A1C13 —BF3 (Lewis acids) ascatalyst and ethanol, n-propanol and n-butanol as co-catalyst. Using Lewis acids as catalyst, theHPTs form molecules with higher molecular weight. Since the raw materials of the reaction are byproducts of other reactions, are not pure and contain various compounds with different M.W andalso different chemical...