3.4- dideutero

A positive iodinating species was postulated to account for the kinetics and isotope effect observed in the iodination of some amines by iodine in aqueous potassium iodide (in some cases in the presence of acetate, lactate, or phosphate ion). The isotope effects (kH/kD values in parenthesis) for these compounds studied were 2,4,6-trideutero-m-dimethylaminobenzenesulphonate ion, 25 °C (1.0) 2,4,6-trideutero-m-dimethyIbenzoate ion, 30 °C (1.4) 2,4,6-trideutero-dimethylaniline, 30 °C, lactate (3.0) 2,4,6-trideuteromethylaniline, 25 °C, acetate (3.2) 2,4,6-trideuteroaniline, 25 °C (3.5), phosphate (4.0) 2,4,6-trideutero-metanilate ion, 35 °C (2.0) 2,4,6-trideutero-m-aminobenzoate ion, 30 °C (4.8), phosphate (3.0) 2,6-dideutero-l-dimethylaminobenzene-4-sulphonate ion, 25 °C, phosphate (1.0) 4-deutero-l-dimethylaminobenzene-3-sulphonate ion, 25 °C, phosphate (1.0). The kinetics of these reactions was given by... 

Cyclodecin ergibt nach Deuteroborierung mit Hexadeutero-diboran und Deuterolyse mit Essigsaure-O-D 43% deuteriertes Produkt, das 81% cis-1,2-Dideutero-cyclodecen enthalt7 ... 

Die Oxo-Gruppe in Oxo-steroiden kann in Gemischen aus l,4-Dioxan/10%iger Schwefelsaure (3 2) an Blei-Kathoden zur Methylen-Gruppe reduziert werden. So erhalt man z.B. aus 3/l-Hydroxy-7-oxo-5a-cholestan 70% d.Th. 3ft-Hydroxy-5a-cholestan (mit Dideutero-Schwefelsaure 3/3-Hydroxy-7,7-dideutero-5a-cholestan)h. 

Bis-[ ( benzo-1,3-oxazol) -yl-(2)-thio]- 343 Bis-[1,4- (bzw. 3,4]-dihydro-naphthy[-(2)-oxy]- 588 Bis-[dimethylamino]- 345 Bis-[4-dimethyIamino-phenyl]- 346 Bis-[4-hydroxy-phenyl]-(2-carboxy-phenyl)- 167 Bis-[4-methoxy-phenyl]-dideutero- 346 Bis-[4-methyl-phenyl]-Bis-f 2-methyl-thiiranyl-(2)]- 570 Bis-[naphthyl-(2)-oxy]- 588 Bis-[naphthyl-(2)-thio]-... 

Amino-2-methyl-1,1 -dideutero- 111 2-Amino-i-(3,4-methylendioxy-phenyl)- 80 1 -Amino-2 -(2 -mcthyl-propyloxy)- 472 2-Amino-l-oxo-l-phenyl- 325 1 -Amino-1 -phenyl -... 

Diphenylmethylen- 497 2a(S),3a(0)-Dithiocarbonato- 340 22,26-Epimino-3/3-hydroxy-5a- 104 2a,3a-Epithio- 340, 448 4a,5a-Epoxy-6-oxo- 549 Hydroxy- 567 3 -Hydroxy- 75, 731 3/3-Hydroxy- 75, 608, 720, 747 5/3-Hydroxy-3/3-acetoxy-6-hydroximino- 521 3/3-Hydroxy-2a-(athoxy-thiocarbonylthio)- 340 3/3-Hydroxy-7,7-dideutero-5a- 608 3/3-Hydroxy-5a, 6a -epoxy- 423 2/3-Hydroxy-3a -mcrcapto- 102 3a-Hydroxy-2/3-mcrcapto- 102 3/3-Hydroxy-2/3-mercapto- 340 3/3-Hydroxy-7-oxo-5a- 608 4a -Hydroxy-6-oxo-5ct - 549 2/3-Hydroxy-3a-thiocyanato- 102 3a-Hydroxy-2/3-thiocyanato-102... 

By a ten-step route ftom a-pinene [7], (15)-(-)-cxo-2,4-dideutero-apopinene was synthesized thrice with different deuterium concentrations. The hydrogen contents (19%, 15.1%, and 6.1%) of the molecules at the C2 position were determined by 200 MHz proton... 

Over zinc oxide it is clear that only a limited number of sites are capable of type I hydrogen adsorption. This adsorption on a Zn—O pair site is rapid with a half-time of less than 1 min hence, it is fast enough so that H2-D2 equilibration (half-time 8 min) can readily occur via type I adsorption. If the active sites were clustered, one might expect the reaction of ethylene with H2-D2 mixtures to yield results similar to those obtained for the corresponding reaction with butyne-2 over palladium That is, despite the clean dideutero addition of deuterium to ethylene, the eth-... 

The most famous mechanism, namely Cossets mechanism, in which the alkene inserts itself directly into the metal-carbon bond (Eq. 5), has been proposed, based on the kinetic study [134-136], This mechanism involves the intermediacy of ethylene coordinated to a metal-alkyl center and the following insertion of ethylene into the metal-carbon bond via a four-centered transition state. The olefin coordination to such a catalytically active metal center in this intermediate must be weak so that the olefin can readily insert itself into the M-C bond without forming any meta-stable intermediate. Similar alkyl-olefin complexes such as Cp2NbR( /2-ethylene) have been easily isolated and found not to be the active catalyst precursor of polymerization [31-33, 137]. In support of this, theoretical calculations recently showed the presence of a weakly ethylene-coordinated intermediate (vide infra) [12,13]. The stereochemistry of ethylene insertion was definitely shown to be cis by the evidence that the polymerization of cis- and trans-dideutero-ethylene afforded stereoselectively deuterated polyethylenes [138]. 

The reaction of (Z,Z)-l,4-dideutero-l,3-butadiene provided mechanistic details on the [2 + 2]- and the [4+2]-cycloaddition of 6 [72], Concerning the former, Scheme 6.20 illustrates that the stereochemical information with regard to the deuterovinyl group that becomes part of the four-membered ring is entirely lost, whereas that of the second deuterovinyl group is completely retained. The former observation is in... 

Scheme 6.20 Steric course of the [2 + 2]-cycloadditions of 1,2-cyclohexadiene (6) to (Z)-/J-deuterostyrene and (Z,Z)-1,4-dideutero-l,3-butadiene.

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