Performance schemes

In order to observe the single-step hole transfer from Py + to inside the DNA, pulse radiolysis of Py-conjugated ODNs with one oxG substituted for G as a hole trap was performed (Scheme 5 Fig. 7). In this case, the oxidation... 

Ogasawara and coworkers have also published a complete series of threefold anionic domino reactions, all of which are based on an initial retro-aldol process. For instance, starting from chiral bicyclo[3.2.1]octenone 2-437, a formal total synthesis of (-)-morphine (2-445) [233] has been successfully performed (Scheme 2.103) [234]. Transformation of 2-437 into the substrate 2-488, necessary for the domino reaction, was achieved in seven linear steps. The domino process was then initiated by simply refluxing a solution of 2-438 in benzene in the presence of ethy-... 

Hydrolytic ring opening of the 1,3-oxazine ring of the tetrahydro-[l,3]oxazino[3,4- ][l,2]oxazin-8-one 389 and subsequent protection of the carboxyl group has been performed (Scheme 61) <1999TL4391>. 

Ha et al. demonstrated that dispersed TPD in a fluorine-containing polyimide matrix as a HTM has significantly improved device performance (Scheme 3.17) [91]. Flexible and fluorinated polyimide as a matrix exhibits the lowest turn-on voltage and a high EL efficiency [92]. 

The Pd(0)-catalyzed electrophilic reaction of allyl acetates (301) with elec-trochemically induced carbanions leading to (302) has been performed (Scheme 115) [436], The electrolysis is carried out in a DM F-Et4NCl04-(Pt) system in the presence of the active hydrogen compound, Ph3P, and Pd(II)(PhCN)2Cl2 at a current density of 0.26 A dm and the allyl acetate (301). 

Various processes were tested, and among others, a Mannich-type reaction was performed (Scheme 20). The yield was modest but the reactor design was appealing and the methodology was further applied in the research group [46]. 

Recently, the synthesis of photochromic compounds containing two or more diarylethene fragments bound either directly or through linkers has been performed. Scheme 32 illustrates one approach to 96 containing two hexafluorocyclopentene-bridged dihetarylethene fragments (05JACS8922). 

Most work on this subject is based on the use of alcohols as reagents in the presence of enantiomerically pure nucleophilic catalysts [1, 2]. This section is subdivided into four parts on the basis of classes of anhydride substrate and types of reaction performed (Scheme 13.1) - desymmetrization of prochiral cyclic anhydrides (Section 13.1.1) kinetic resolution of chiral, racemic anhydrides (Section 13.1.2) parallel kinetic resolution of chiral, racemic anhydrides (Section 13.1.3) and dynamic kinetic resolution of racemic anhydrides (Section 13.1.4). 

Pyridone is O-alkylated more readily than normal amides, because the resulting products are aromatic. With soft electrophiles, however, clean N-alkylations can be performed (Scheme 1.7). The Mitsunobu reaction, on the other hand, leads either to mixtures of N- and O-alkylated products or to O-alkylation exclusively, probably because of the hard, carbocation-like character of the intermediate alkoxyphosphonium cations. Electrophilic rhodium carbene complexes also preferentially alkylate the oxygen atom of 2-pyridone or other lactams [20] (Scheme 1.7). 

Electrophiles which enable four substitutions at the same carbon atom include C13CN02 and CI3CSCI both compounds yield tetraalkyl orthocarbonates on treatment with alcoholates [150], In polyhalomethanes selective substitutions of the most reactive halide are possible [153] but not always easy to perform (Scheme 4.38). 

A similar borderline system, fran -bis[2-(2-chloroethyl)pyridine]palladium chloride (1), has been prepared and structurally characterized by X-ray spectroscopy and computational study.2 A study on the elimination reaction of (1) induced by quinuclidine in acetonitrile has been performed (Scheme 1). The results suggest that the initial product of elimination is a palladium complex of vinylpyridine and that displacement from this complex is partially rate determining in the formation of the uncoordinated product. Despite experimental efforts, it was not possible to distinguish between two possible mechanisms, E2 concerted or ElcB. 

The selenetanes that have been described in the literature have been constructed via three types of reactions. Selenetane derivatives are generally prepared via the [2+2] two-component syntheses (Schemes 8 and 9 Equations 3-7). The [1+3] two-component syntheses via the reaction of a selenium nucleophile with a three-carbon unit have been carried out (Scheme 6, and Equations 8-10, 12, and 13). One-component syntheses via rearrangement-cyclization have also been performed (Scheme 7). 

To identify potential dipolarophiles, a series of competition experiments were performed (Scheme 7.45).117 While inclusion of terminal acetylenes resulted in preferential silacyclopropene 99c or dioxosilacyclopentane 161 formation, the desired oxasilacylopentene (163) was obtained when diethylacetylene dicarboxylate was added... 

To clarify the reaction mechanism, the reaction of tricrotylborane with nitrobenzene was performed (Scheme 4). Amine (8) (80%) proved to be the sole product of crotylborationof PI1NO2. A mixture of dimethyl-l,5-hexadienes (7 isomers, 80%) was also obtained. 

Addition reactions of saccharide thiols to glucals have been performed ( Scheme 54, compare with Scheme 26). The a-linked thiooligosaccharide was the main product but the -anomer and the product resulting from a displacement of the 3-0-acetate were also isolated (ratios 1 1) [174],... 

Therefore, our first idea was to 0-acylate simple enolates with phosgene. In a first course of attempts, we investigated the reaction of phosgene with alkaline metals enolates. For example we prepared lithium enolate of acetaldehyde through cleavage of tetrahydrofuran by n- butylllthium (Ref. 116) and reacted with phosgene under various conditions. Unfortunately, no trace of vinyl chloroformate was found in all experiments performed [Scheme 90]. 

Nuc E), forming a dipole for cycloaddition, to produce (Scheme 2 (3)) a cyclic imino species. The latter general type of reaction (Scheme 1 (2)), involving the addition of an electrophile (E) to the ligated nitrile, yields (Scheme 2 (4)) azavinylidene products, [M]-N=C(E)R. Sequential nucleophilic-electrophilic additions have also been performed (Scheme 3), leading to a stepwise and alternative mode of ligand activation. 

Based on this knowledge the first uncharged but nevertheless readily water-soluble precursor PPP 27 (Pn % 30) were recently obtained. As the degree of protonation may play an important role in the profound characterization of polyamines like 27, titration studies were also performed (Scheme 6). 

Some modified boronic acids were allowed to enter a resin-to-resin transfer reaction (RRTR) to participate in a borono-Mannicli MCR with a substrate bound to a different polymer. By doing so the authors avoided a difficult work-up of boronic acids, which often tend to form oligo and polyanhydrides. Thus, starting from the (DEAM-PS)-bound 3-amino boronic acids (438), Ugi reactions yielding dipeptides such as (441) have been performed (Scheme 90). 

Polarographic reductions of 2-methylenehexahydroazepines were performed (Scheme 147). The half-wave potentials are linearly related to the Zo-, and Scu Hammett substituent constants. 

A number of technological methods are applied for petroleum drying. The choice of method for petroleum drying and performance scheme employed substantially depends on the amount and condition of water present. 

The deuterium was quantitatively transferred into the expected position to give 70 and 71 as the reaction products. No H-D-exchange of the substrate with the reaction medium was observed. As a final confirmation of the strictly intramolecular process a cross-over experiment of non- and dideuteriated material was performed (Scheme 12). MS-analysis clearly demonstrated that only do and d2-product (i.e. 75 and 76) was formed from 49 and 73, whereas in case of an intermolecular rearrangement also drmaterial 77 and 78 should have been generated. 

To improve the selectivity and yield of 16a, various synthetic methods were proposed, and as an improved method, a procedure using compound 11 as a key intermediate was performed (Scheme 3). The 2 - and 4"-hydroxy groups and the... 

Furthermore, since the ethynyl group can be protected by silylation, the resulting trimeriza-tion products may be used as second starting materials after deprotection, By using this strategy, construction of the Starburst dodecaketone 49, which is the precursor of dode-cacarbene contained in the network polymer 46, was successfully performed (Scheme 11-6). 

---