Olefins, trans

The complex OsH(OH)(CO)(P Pr3)2 also reacts with methyl acrylate, methyl vinyl ketone, and allyl alcohol.91 Reaction with methyl acrylate leads to OsH(OH) (COXrf-CH2=CHC02MeXP Pr3)2 containing the olefin trans to the hydride ligand. In solution, this complex releases the olefin to generate the starting complex. The thermodynamic magnitudes involved in the equilibrium have been determined in toluene-t/a by 31P 1H NMR spectroscopy. The values reported are AH° = 17.0 0.5 kcal-mor1 and AS° = 54.0 1.2 cal-K 1-mol 1. In the presence of the methyl vinyl ketone complex OsH(OH)(CO)(P Pr3)2 affords 0sH CHCHC(0) Me (CO)(P Pr3)2 and water, whereas in the presence of allyl alcohol the loss of... 

Table 13 Values of p and m for ring-substituent and solvent effects in the bromination of aromatic olefins trans-Ar—C(R)=CHR in methanol at 25°C.

We have studied the effect of cavitating ultrasound on the heterogeneous aqueous phase hydrogenation of a 5-2-buten-l-ol (C4 olefin) and a5-2-penten-l-ol (C5 olefin) on Pd-black (1.5+0.1 mg catalyst) to form the lra/ 5-olefins trans-2-buten-l-ol and fra/3s-2-penten-l-ol) and saturated alcohols (1-butanol and 1-pentanol, respectively). These chemistries are illustrated in Scheme 2. A full analysis of this study has been recently presented [10]. 

When the addition reactions of tellurium tetrachloride or tellurium tetrabromide were carried out in the presence of an alcohol with a cycloalkene as the olefin, trans-2-alkoxycycloalkyl tellurium trihalides were isolated in yields ranging from 30 to 80%4... 

Work on the pyridine-modified ozonization of tetramethylethylene showed that pyridine oxide is not-a product of ozonization (8). Most of the pyridine (— 90% ) remains unchanged during double bond cleavage. Only one mole of acetone, rather than two, is formed for each mole of olefin oxidized. Other work with a disubstituted olefin, trans-4-octene, showed that ozonides are formed in the reaction so that the reaction of pyridine with ozonide to form acid and aldehyde cannot occur (9). An NMR study of trans-4-octene ozonolysis in the presence of pyridine using 1,2-dichloroethane as the solvent shows that aldehyde and hydroxyl-containing material (carboxylic acid, peracid, and other OH species) are formed directly during double bond cleavage. 

Starting Olefin trans-Stilbene trans-Stilbene °C acetone -78 acetophenone 0 1, 4-Trioxolane 3,3-dimethyl- 5-phenyl 3-methyl-3,5- diphenyl Formula C10H12O C15H14O ... 

Greenwood91,92 demonstrated the formation of primary ozonides in the reaction of some reaction with liquid ozone gave products that formed glycols on mild reduction with isopropylmagnesium bromide. On the other hand, primary ozonides have not been detected with certainty in the case of cis-olefins.88 91 The reaction of cis-3-hexene,93 eis-2-butene, cis-2-pentene, and ethylene92 with ozone at —112° in pentane led to extremely explosive substances, which could be primary ozonides. In the... 

Bolland, J.L. Gee, G. Kinetic studies in the chemistry of rubber and related materials. II. The kinetics of oxidation of unconjugated olefins. Trans. Faraday Soc. 1946, 42, 236-243. 

J. H. Knox, K. C. Waugh, Activated chloroalkyl radicals in the chlorination of trichloroethylene and other olefins, Trans. Faraday Soc. 65 (1969) 1585. 

As with many computational models of catalysis, we need a key step in the mechanism to model. Since chain growth occurs with the olefin trans to the coordinated oxygen, workers at Shell have modeled the cis/trans ratio in order to determine how to modify the ligand to force trans coordination (Fig. 12). 

Hz is a typical value for an olefinic trans coupling constant and identifies the formation of the corresponding (i )-alkene by trans-hydrogenation of the substrate. 

No. X Base (pK j Solvent 1-Olefin (%) trans-lcis- 2-Olefin... 

The following shorthand designation may be used to describe the chemical structure of fatty acids the number of carbon atoms in the chain separated by a colon from the number of unsaturated bonds is followed by a set of parentheses containing the numbers of the double-bond positions and the letters c, t, or a to indicate whether a bond is cis-olefinic, trans-olefinic, or acetylenic. The position of double bonds is numbered from the carboxyl group. 

As expected, the cis/trans diastereoselectivity is influenced by the structure of the catalyst precursor, and is controllable by choosing a proper catalyst and polymerization conditions. The enantioselectivity (the relative stereochemistry between the rings) of PMCP is also affected by the catalyst structure. Complexes la, lb (Figure 19.2), and 2a, which give atactic poly(a-olefin)s, produce atactic PMCP, and the isoselective catalysts 3 and 4a yield isotactic PMCPs. These differences in enantioselectivity versus catalyst type are consistent with those for the polymerization of a-olefins. trans-Isotactic polymers can be optically active (chiral) if homochiral catalysts are used. The Waymouth research group showed that the MAO-activated homochiral ansa-zirconocene BINOL complex 5 (BINOL = l,l -bi-2-naphtholate Figure 19.2) gave optically active trany-polymer. 

Dattelbaum DM, Itokazu MK, Dia NYM et al (2003) Mechanism of metal-to-ligand charge transfer sensitization of olefin trans-to-cis isomerization in the fac-[Re (phen)(CO)3(l,2-bpe)]" cation. J Phys Chem A 107 4092-4095... 

One-pot Synthesis of / -Cyanohydrins from Olefins, trans-/3-Cyanohydrins can be prepared efficiently by treating the corresponding olefins with bis(trimethylsilyl) peroxide and TMSCN in a reaction promoted by a bulky zirconium catalyst (eq 9). This reaction was much faster and cleaner in the presence of 20 mol % of PhsPO. A similar reaction performed in the presence of TMSOAc, albeit with a different catalyst Zr(0 Pr)4, resulted in the formation of trans-(i-acetoxy alcohols. Chlorohydrins can also be prepared if the corresponding olefins are treated with SnCLj and TMSCl in the presence of bis(trimethylsilyl) peroxide. ... 

An extensive group of C studies by Clark and co-workers concerned with all of the above themes, e.g. ir-bond bonding in olefins, trans influence and Tt-bonding in a-aryl derivatives has appeared [241]. 

Booth, D., Dainton, F.S. and Ivin, K.J. (1959) Thermodynamics of formation and absorption spectra of 1 1 complex between sulfur dioxide and olefins. Trans. Faraday Soc., 55, 1293-... 

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