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Woodward

Woodward L A 1967 General introduction Raman Spectroscopy Theory and Practice vol 1, ed H A Szymanski (New York Plenum)... [Pg.1226]

Yethira] A and Woodward C E 1995 Monte Carlo density functional theory of nonuniform polymer melts J Chem. Phys. 102 5499... [Pg.2384]

Woodward J T, Ulman A and Schwartz D K Self-assembled monolayer growth of octadecylphosphonic acid on mica Langmuir 12 3626-9... [Pg.2635]

The Woodward-Hoffmann method [52], which assumes conservation of orbital symmetry, is another variant of the same idea. In it, the emphasis is put on the symmetries of molecular orbitals. Longuet-Higgins and Abramson [53] noted the necessity of state-to-state correlation, rather than the orbital correlation, which is not rigorously justified (see also, [30,44]). However, the orbital symmetry conservation rules appear to be very useful for most themial reactions. [Pg.344]

Electi ocyclic reactions are examples of cases where ic-electiDn bonds transform to sigma ones [32,49,55]. A prototype is the cyclization of butadiene to cyclobutene (Fig. 8, lower panel). In this four electron system, phase inversion occurs if no new nodes are fomred along the reaction coordinate. Therefore, when the ring closure is disrotatory, the system is Hiickel type, and the reaction a phase-inverting one. If, however, the motion is conrotatory, a new node is formed along the reaction coordinate just as in the HCl + H system. The reaction is now Mdbius type, and phase preserving. This result, which is in line with the Woodward-Hoffmann rules and with Zimmerman s Mdbius-Huckel model [20], was obtained without consideration of nuclear symmetry. This conclusion was previously reached by Goddard [22,39]. [Pg.347]

We have seen (Section I) that there are two types of loops that are phase inverting upon completing a round hip an i one and an ip one. A schematic representation of these loops is shown in Figure 10. The other two options, p and i p loops do not contain a conical intersection. Let us assume that A is the reactant, B the desired product, and C the third anchor. In an ip loop, any one of the three reaction may be the phase-inverting one, including the B C one. Thus, the A B reaction may be phase preserving, and still B may be attainable by a photochemical reaction. This is in apparent contradiction with predictions based on the Woodward-Hoffmann rules (see Section Vni). The different options are summarized in Figure 11. [Pg.347]

In the following decades, chemists tried to utilize more and more the knowledge on reactions which had already been gained. A number of landmark syntheses represent the change to modern chemistry, such as the synthesis of the estrogenic steroid equilenin (W. Bachmann, 1939), of pyridoxine (K. Folkers, 1939), and of quinine (R.B. Woodward, W. von E. Doering, 1944) [23]. [Pg.568]

For Woodward-Hoffm an allowed thermal reactions (such as the con rotatory ring opening of cyclobulan e), orbital symmetry is conserved and there is no change in orbital occupancy. Hven though bonds are made and broken, you can use the RHFwave fun etion. [Pg.46]

For many reasons, including the Woodward-IIoffm an rules that describe the likelihood of reaction based on arguments about the shapes of orbitals, it is desirable to be able to visualize molecular orbitals. [Pg.243]

Suprafacial attack of me ethene molecule on anotlier (left) is not permitted by the Woodward-Hoffmann id the alternative antarafacial mode of attack is sterically unfavourable. Suprafacial attack is however permitted Diels-Alder reaction between butadiene and ethene (right). [Pg.308]

Seetion treats the spatial, angular momentum, and spin symmetries of the many-eleetron wavefunetions that are formed as anti symmetrized produets of atomie or moleeular orbitals. Proper eoupling of angular momenta (orbital and spin) is eovered here, and atomie and moleeular term symbols are treated. The need to inelude Configuration Interaetion to aehieve qualitatively eorreet deseriptions of eertain speeies eleetronie struetures is treated here. The role of the resultant Configuration Correlation Diagrams in the Woodward-Hoffmann theory of ehemieal reaetivity is also developed. [Pg.3]

Along "Reaction Paths", Orbitals Can be Connected One-to-One According to Their Symmetries and Energies. This is the Origin of the Woodward-Hoffmann Rules I. Reduction in Symmetry... [Pg.184]

Along "reactionpaths", configurations can be connected one-to-one according to their symmetries and energies. This is another part of the Woodward-Hoffmann rules... [Pg.290]

The way the substituents affect the rate of the reaction can be rationalised with the aid of the Frontier Molecular Orbital (FMO) theory. This theory was developed during a study of the role of orbital symmetry in pericyclic reactions by Woodward and Hoffinann and, independently, by Fukui Later, Houk contributed significantly to the understanding of the reactivity and selectivity of these processes. ... [Pg.4]

Woodward and Baer in 1948 " ". These authors noticed a change in endo-exo selectivity when... [Pg.18]

Woodward tried all these different routes except the one based on the 1,6-dicarbonyl relationship. AU were successful, but he eventually chose the route corresponding to a and c. He discusses this synthesis at length in the 1963 reference. [Pg.65]

This is the allowed process by the Woodward-Hoffmaim rules (see Tedder, Part 3, pp. 383-387 or Norman p. 292 ff if you want to know more). There are obviously two disconnections for any given cyclobutane but it is often easy to see the better at once. How would you make ... [Pg.94]

An interesting case are the a,/i-unsaturated ketones, which form carbanions, in which the negative charge is delocalized in a 5-centre-6-electron system. Alkylation, however, only occurs at the central, most nucleophilic position. This regioselectivity has been utilized by Woodward (R.B. Woodward, 1957 B.F. Mundy, 1972) in the synthesis of 4-dialkylated steroids. This reaction has been carried out at high temperature in a protic solvent. Therefore it yields the product, which is formed from the most stable anion (thermodynamic control). In conjugated enones a proton adjacent to the carbonyl group, however, is removed much faster than a y-proton. If the same alkylation, therefore, is carried out in an aprotic solvent, which does not catalyze tautomerizations, and if the temperature is kept low, the steroid is mono- or dimethylated at C-2 in comparable yield (L. Nedelec, 1974). [Pg.25]

Later examples of the olefination of carbonyl compounds, which are extremely sensitive towards acid or basc catalyzed rearrangements, have been given by G. Buchi and by R.B. Woodward. [Pg.32]

Conjugated dienes are often converted into 2,3-unsaturated 1,4-dioIs by successive treatment with peracids and hydroxides (R.B. Woodward, 1957). [Pg.124]


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Alkenes Woodward’s procedure

Allowed reaction, Woodward-Hoffmann rules

Amines Woodward’s reagent

Antarafacial, Woodward-Hoffmann rules

Aromaticity Woodward-Hoffmann rule

Components Woodward-Hoffmann rule

Conrotatory, Woodward-Hoffmann rules

Cyclization Woodward-Hoffmann Rules

Cycloaddition reactions Woodward-Hoffmann rules

Diels-Alder reaction Woodward-Hoffmann rules applied

Diels-Alder reactions Woodward-Hoffmann rules

Disrotatory, Woodward-Hoffmann rules

Electrocyclic reactions Woodward-Hoffmann rules for

Electrocyclic reactions Woodward-Hoffmann treatment

Erythromycin Woodward

Explaining Woodward-Hoffmann rules

Explanations for the Woodward-Hoffmann Rules

Forbidden reaction, Woodward-Hoffmann

Forbidden reaction, Woodward-Hoffmann rules

Generalized Woodward-Hoffmann rules

Hydroxylation Woodward-Prevost

Molecular orbitals Woodward-Hoffman rules

Notation Woodward-Hoffmann

Orbital Symmetry Correlations Woodward-Hoffman Rules

Orbital correlation diagrams Woodward-Hoffmann

PREVOST WOODWARD Olefin

PREVOST WOODWARD Olefin hydroxylation

Pericyclic reactions Woodward-Hoffmann rules for

Photochemical reactions Woodward-Hoffmann rule

Photochemistry Woodward-Hoffmann

Polyenes (Woodward-Fieser rules)

Qualitative theories Woodward-Hoffmann rules

Reaction Woodward-Hoffmann allowed

Reaction mechanism Woodward-Hoffmann rules

Reserpine Woodward

Scientist of the Decade Robert Bums Woodward

Steroids Woodward

Strychnine Woodward

Suprafacial, Woodward-Hoffmann rules

T Woodward

The Conservation of Orbital Symmetry (Woodward-Hoffmann Rules)

The Generalised Woodward-Hoffmann Rule

The Photochemical Woodward-Hoffmann Rule

The Woodward-Fieser Rules for Dienes

The Woodward-Hoffmann Rules

The Woodward-Hoffmann rules and molecular orbitals

Total Synthesis of Woodwards Carbamate Intermediate

Validity of the Woodward-Hoffmann Rules

Violations of the Woodward-Hoffmann

Violations of the Woodward-Hoffmann rules

WOODWARD Peptide synthesis

Wittig rearrangement Woodward-Hoffmann rules

Woodward 2 Hydrogenation

Woodward Hoffmann theory

Woodward R. B., and Hoffmann

Woodward and Doering

Woodward cis-dihydroxylation

Woodward cw-dihydroxylation

Woodward glycolization

Woodward governor

Woodward hydroxylation

Woodward method

Woodward modification

Woodward modification Prevost reaction

Woodward modification of the Prevost

Woodward modification of the Prevost reaction

Woodward reaction

Woodward reagent

Woodward rules

Woodward studies

Woodward, Edward

Woodward, John

Woodward, Joseph Janvier

Woodward, Peter

Woodward, Robert

Woodward, Robert Bums

Woodward, Robert Burns

Woodward, Robert organic synthesis

Woodward, Scott

Woodward, William

Woodward-Fieser

Woodward-Fieser rules

Woodward-Hoffinann

Woodward-Hoffman

Woodward-Hoffman Orbital Correlation Diagrams

Woodward-Hoffman method

Woodward-Hoffman orbital correlation rules

Woodward-Hoffman rule of electrocyclic reactions

Woodward-Hoffman rules

Woodward-Hoffman rules, Diels-Alder reactions

Woodward-Hoffmann

Woodward-Hoffmann Correlation-diagram Approach

Woodward-Hoffmann Rules and Topology

Woodward-Hoffmann correlation

Woodward-Hoffmann correlation diagrams

Woodward-Hoffmann cycloaddition

Woodward-Hoffmann diagrams

Woodward-Hoffmann exclusion rules

Woodward-Hoffmann forbidden and allowed

Woodward-Hoffmann forbidden and allowed reactions

Woodward-Hoffmann general rule

Woodward-Hoffmann neutral

Woodward-Hoffmann orbital

Woodward-Hoffmann orbital symmetry

Woodward-Hoffmann orbital symmetry concept

Woodward-Hoffmann orbital symmetry rules

Woodward-Hoffmann pericyclic

Woodward-Hoffmann rales

Woodward-Hoffmann reactions

Woodward-Hoffmann rules

Woodward-Hoffmann rules 1.3- sigmatropic rearrangements

Woodward-Hoffmann rules Claisen rearrangement

Woodward-Hoffmann rules alkene dimerization

Woodward-Hoffmann rules cheletropic reaction

Woodward-Hoffmann rules cycloaddition

Woodward-Hoffmann rules cycloadditions

Woodward-Hoffmann rules definition

Woodward-Hoffmann rules electrocyclic reactions

Woodward-Hoffmann rules for

Woodward-Hoffmann rules for cycloaddition reactions, table

Woodward-Hoffmann rules for electrocyclic reactions, table

Woodward-Hoffmann rules for photochemical reactions

Woodward-Hoffmann rules for sigmatropic rearrangements, table

Woodward-Hoffmann rules general selection rule

Woodward-Hoffmann rules generalised rule

Woodward-Hoffmann rules method

Woodward-Hoffmann rules pericyclic reaction

Woodward-Hoffmann rules photochemical

Woodward-Hoffmann rules sigmatropic reaction

Woodward-Hoffmann rules stereochemistry

Woodward-Hoffmann rules substituent effects

Woodward-Hoffmann rules summary

Woodward-Hoffmann rules thermal reactions

Woodward-Hoffmann rules, conservation

Woodward-Hoffmann rules, for cycloaddition

Woodward-Hoffmann rules: examples

Woodward-Hoffmann selection rules

Woodward-Hoffmann transition states

Woodward-Hoffmanns Generalized Rules for Pericyclic Reactions

Woodward-Hoffmann’s rules

Woodward-Hofmann rule

Woodward-Prevost method

Woodward-Prevost reaction

Woodward-Prevost synthesis

Woodward-Wilds

Woodwards Rules for Enones

Woodward’s Reagent K

Woodward’s chlorophyll synthesis

Woodward’s reagent

Woodward’s rules

Woodward’s rules for

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