B-Deuterium Isotope Effect in Solvolysis of 1 ,2-Dimethyl-exo-2- -norhornyl p-Nitrohenzoate

Secondary (:-deuterium isotope effects have been shown to be remarkably constant with change of solvent1. The ratio, kH/kD, , was 1.22 in solvolysis of 1-phenylethyl chloride in ethanol-water mixtures ranging from 50 vol 0/o to 80 vol O/o of ethanol. It was proposed that the transition state is very nearly the same in all the solvents studied. The yields of styrene (as an elimination product) were between 1 and 3 percent

Mass Spectra of Labeled Cyclopentanols

The fragmentation of cyclopentanol has been studied by employing the deuterium labeling technique. Starting from the molecular ion the following specific processes could be established: loss of H from the position 1, loss of CH3 formed mainly from 2 (or 5) position after a-scission, loss of H 2 0 as a 1,3-elimination, and loss of C2H 5 generated from 2 and 3 or 4 and 5 positions plus one hydrogen from position 5 or 2, respectively. The results are discussed

Reactions of Cyclopropylmethyl Benzenesulfonate. Energies and Entropies of Activation

The solvolyses of cyclopropylmethyl derivatives are accelerated and seem to proceed through the formation of non-cla1ssical carbornium i\u27Onsn. These reacti•ons are a•ls:o very often accompa1111ied by extensive rearrangements6 • Thus, the acetolysis of cyc1opropylmethyl benzenesulfonate proceeds simultaneously w;ith a competitive internal rearrangement to products which are 250 times less reactive than the starting materiaF. In the course of our investigation o[ the mecha111ism of these two closely related reactions, we w&nted to gain some information aibout the. corresponiling free energies and entropies of activation

Secondary Deuterium Isotope Effects in Solvolysis of Cyclopentyl p-Bromobenzenesulfonate in Dioxane-Water Mixtures. Stereochemistry of E1 and SN 1 Reactions

In the continuation of our study1 on the rela:tionship between the magnitude of secondary deuterium isotope effects and the reaction pathways in solvolytic SNl and El reaotions, we report the results obtained in differentdiox·ane- water (D- W) mixtures wi·th specifd.cally deuternrted cyclopenrtylbrosylates. For this purpose, required cyclopentainol, cyclopentanol-1-d (a-d), cis-cyclopentanol-2-d (cis-B-d), trans-cyclopentanol-2-d (trans-B-d) and cyclopentarrol-2,3,5,4-d4 (B-d.;) were prepared as described by Streitwieser et al.2 The correspond~ng b.rosylates were prepared by rthe usual Tipson procedure3 •The deuterium content was greater than 93 0/o 1in all of deuterated compounds as was determined by mass spectral analysis

Mass Spectra of Labeled Cyclopentanols

The fragmentation of cyclopentanol has been studied by employing the deuterium labeling technique. Starting from the molecular ion the following specific processes could be established: loss of H from the position 1, loss of CH3 formed mainly from 2 (or 5) position after a-scission, loss of H 2 0 as a 1,3-elimination, and loss of C2H 5 generated from 2 and 3 or 4 and 5 positions plus one hydrogen from position 5 or 2, respectively. The results are discussed

Deuterium Scrambling During Stereochemical Equilibration of endo- and exo-Norbornanol-3,3-d2

Herewith we wish report about an interesting case of deuterium scrambling during the attempted preparation of exo-norbornanol-3,3-d2 from the endoisomer through equilibration with the aid of fluorenone

Mass Spectra of Bicyclo[2.2.1 ]-2-heptanols

The fragmentation of bicyclo[2.2.1]-2-heptanol, endo- (I) and exo- (Ia), 1-methylbicyclo[2.2.1]-2-heptanol, endo- (II) and exo( IIa) and 2-methylbicyclo[2.2.1]-2-heptanol, endo- (III) has been studied by employing the deuterium labelling technique. The results obtained indicate · that the existence of nonclassical carbonium ion is of no significant importance during the fragmentation of the molecular ion of these alcohols and that the dehydration of the molecular ion is stereospecific regarding the position of eliminated hydrogen

1,3-Hydrogen Migration in the Solvolysis of 2-(L\u27.1 3-Cyclopentenyl)ethyl p-Toluenesulfonate

2-(Ll 3-Cyclopentenyl)ethyl-1,1-d2 tosylate was prepared and solvolyzed in 80 per cent aqueous acetic acid. Conversion of the so1volysis products to exo-2-norbornanol and integration o-f the peak areas of its n.m.r. spectrum indicates 10-15 per cent of 1,3-deuterium migration. The hypothesis is advanced that this migration must have taken place after the rate determining step of the solvolysis. exo-2-Norbornanol-d2 resulting from this reaction was converted to the corresponding p-bromobenzenesulfonate and solvolyzed in acetic acid. Possible explanations for the observed secondary isotope effect (kH/kD 1.13) are given

Reactions of Cyclopropylmethyl Benzenesulfonate. Energies and Entropies of Activation

The solvolyses of cyclopropylmethyl derivatives are accelerated and seem to proceed through the formation of non-cla1ssical carbornium i\u27Onsn. These reacti•ons are a•ls:o very often accompa1111ied by extensive rearrangements6 • Thus, the acetolysis of cyc1opropylmethyl benzenesulfonate proceeds simultaneously w;ith a competitive internal rearrangement to products which are 250 times less reactive than the starting materiaF. In the course of our investigation o[ the mecha111ism of these two closely related reactions, we w&nted to gain some information aibout the. corresponiling free energies and entropies of activation

Mass Spectra of Bicyclo[2.2.1 ]-2-heptanols

The fragmentation of bicyclo[2.2.1]-2-heptanol, endo- (I) and exo- (Ia), 1-methylbicyclo[2.2.1]-2-heptanol, endo- (II) and exo( IIa) and 2-methylbicyclo[2.2.1]-2-heptanol, endo- (III) has been studied by employing the deuterium labelling technique. The results obtained indicate · that the existence of nonclassical carbonium ion is of no significant importance during the fragmentation of the molecular ion of these alcohols and that the dehydration of the molecular ion is stereospecific regarding the position of eliminated hydrogen