High-level Computational Study of the Site-, Facial- and Stereoselectivities for the Diels-Alder Reaction Between o-Benzoquinone and Norbornadiene‡
نویسندگان
چکیده
Ab initio and DFT quantum chemical calculations have been applied to a study of the Diels-Alder reaction of o-benzoquinone as diene and norbornadiene as dienophile. Transition states for the different reactions are located and activation energies estimated. The prefered exo-π-facial selectivity and exo,endo-stereoselectivity exhibited in this cycloaddition are readily predicted using RHF/3-21G or higher levels of calculations. Differences between experimentally observed results and calculations may be explained by the postulation of a second, nonconcerted biradical mechanism leading to formation of hetero Diels-Alder products.
منابع مشابه
Diels–Alder [4+2] Cycloadditions of C20 with Some Diene and 1,2- Dioxo Compounds: A Theoretical Study
Diels–Alder [2+4] cycloaddition products of the reaction between C20 and C4H4X2 or C2O2X2 (X = H, F, Cl, CH3, NH2, NO2, and OH) were studied atB3LYP level of theory with 6-31G, 6-31G(d, p) and 6-311G(d, p) basis...
متن کاملREACTION OF 4-METHYL- 1 2,4-TRIAZOLINE- 3,5-DIONE WITH DI AND TRI-SUBSTITUTED STYRENES S.E. Mallakpour* and G.B. Butler**
2,4,6-Triisopropylstryrene was synthesized in a single step via the Witting Reaction from the corresponding aldehyde. The reaction of three styrene's derivatives, 2,6-dimethylstyrene, 2,4,6-trimethylstyrene, and 2,4,6- triisopropylstyrene with 4-methyl-l,2,4-triazoline-3,5-dion(M eTD) was investigated. These reactions are instantaneous at room temperature and lead to the formation of 2: 1 ...
متن کاملA competitive Diels-Alder/1, 3-dipolar cycloaddition reaction of1-H-imidazole 3-oxide toward sulfonyl methane. A DFT study on the energetic and regioselectivity
The dual diene/1,3-dipolar character of 1-H-imidazole 3-oxide, HIO 1, allows this compound toparticipate in a competitive Diels-Alder (DA)/1,3-dipolar cycloaddition (13DC) reaction toward C=Sdouble bond of the electro-deficient sulfonyl methane SFM 2. The B3LYP/6-311++G(d,p) calculatedrelative Gibbs free energies indicate that among the studied 13DC and DA reactions, former iscompletely preferr...
متن کاملSynthesis and Diels–Alder cycloaddition reaction of norbornadiene and benzonorbornadiene dimers
Dimeric forms of norbornadiene and benzonorbornadiene were synthesized starting with known monobromide derivatives. The Diels-Alder cycloaddition reaction of dimers with TCNE and PTAD was investigated and new norbornenoid polycyclics were obtained. All compounds were characterized properly using NMR spectroscopy.
متن کاملبررسی تجربی و محاسباتی سنتز پلی یورتان های ترمیم پذیر بر پایه HTPB با استفاده از واکنش دیلز- آلدر فوران/مالئیمید
The reversibility of the Diels-Alder reaction can be used advantageously in polyurethane materials to endow them with recyclable, thermally reversible properties and self-healing ability to expand their application range. In this paper, linear and crosslink polyurethanes based on HTPB, which exhibit thermal reversibility through Diels-Alder and retro Diels-Alder reactions, were prepared and cha...
متن کامل