Adamantyl chloride

That maximum acceleration occurs when the vacant p orbital is parallel to the plane of the cyclopropyl ring can be seen from the solvolysis of spiro[cyclo-propane-l,2 -adamantyl] chloride (71). The carbocation formed by departure of Cl is unable to adopt the geometry of the bisected cyclopropylcarbinyl cation, but can orient its empty p orbital properly to form the bicyclobutonium ion. This compound solvolyzes 103 times more slowly than 1-adamantyl chloride.82 On the other hand, 72 solvolyzes 10s times faster than 73. The cation from 72 does have its p orbital parallel to the plane of the ring as in the bisected cyclopropylcarbinyl cation.83... 

Another study by Fleming and coworkers examined the stereoselectivity of the titanium tetrachloride catalysed reaction of the allylsilane 137 with 1-adamantyl chloride... 

Buckle and Fleming studied the reactions of the allenylsilane 145 with 1-adamantyl chloride (equation 108) and with isobutyraldehyde and found these Sg2 reactions to be stereospecifically anti to a very high degree175. 

Competition experiments have been carried out to determine the relative reactivities of 23 alkyl chlorides toward allyltrimethylsilane in the presence of ZnCh. The kre scale has been found to span 11 orders of magnitude from the least reactive 1-adamantyl chloride to the most reactive bis(p-methoxyphenyl)methyl chloride384. By contrast, analogous acetals RCH(OMe)2 exhibited very little differences in reactivity385. 

Having noted that two correlations (Figs. 10 and 11), which appeared at first sight to support fully the choice of t-butyl chloride as a model compound, cannot be completely explained, it is not surprising that rates of a solvolysis of 1-adamantyl chloride do not correlate well with Y as shown in Fig. 12 (Morten, 1975). Similar... 

Figure 12. Correlation of solvolytic rate constants for 1-adamantyl chloride [45, X= Q] at 25° and Y (data from Bentley, 1971).

For cases where no change of mechanism occurs, the use of m as a measure of transition state structure may also be unreliable. For example, the observed m values for 1-adamantyl chloride, bromide and tosylate are 1 28 (Schleyer and Nicholas, 1961), 1 08 (Raber et al., 1970), and 0 97 (Kevill et al., 1970), respectively. This appears to... 

The same Japanese chemists5 found that alcohols are converted in high yield into chlorides by reaction with dichlorocarbene generated in this way. Thus 1-adamantyl alcohol is converted into 1-adamantyl chloride in 94% yield, and benzyl alcohol into benzyl chloride in 90% yield. The reaction proceeds with predominant retention of configuration (SNf). 

Equation (50) correlates rate constants for a number of solvolysis reactions and Figure 13 illustrates the Grunwald-Winstein plot for the solvolysis of z-butyl chloride against a K value from 1-adamantyl chloride where w = 0.78. 

Construct a Grunwald-Winstein plot and comment briefly on the magnitude of the slope. The y, Ad parameter is determined from the solvolysis of 1 -adamantyl chloride. 

T.W. Bentley and G. Carter, The Sn2-Sn1 Spectrum. 4. The Sn2 (Intermediate) Mechanisms for Solvolyses of rcrf-Butyl Chloride A Revised F Scale of Solvent Ionising Power Based on Solvolyses of 1-Adamantyl Chloride, J. Am. Chem. Soc., 1982,104, 5741. 

In this correlation the solvolysis of 1-adamantyl chloride is employed as the reference reaction (7,). The slope m is consistent with a transition state with about 1/3 carbenium ion character of that of the reference reaction (where full carbenium ion character is assumed to be expressed). 

Adamantyl chloride [935-56-8] M 170.7, m 1643-165.6 . Crystallise the chloride from aqueous MeOH and sublime it at 100 /12torr. It also crystallises from MeOH at -70 . [Stetter et al. Chem Ber 92 1629 7959, Schleyer Nicholas J Am Chem Soc 83 2700 1961, Beilstein 5 IV 469.]... 

Kevill and co-workers first address the much-debated issue of nucleophilic involvement in solvolysis of tert-butyl derivatives. Interestingly, the tert-butyl sulfonium salt shows more rate variation with solvent changes than does the 1-adamantyl salt. In particular, the tert-butyl salt shows a rate increase in aqueous TFEs (where both Y and N increase) that is not found for 1-adamantyl. Because a variation in Y cannot explain the result, Kevill argues that the tert-butyl derivative is receiving nucleophilic solvent assistance. On the basis of the available evidence, Harris et al. (Chapter 17) propose that tert-butyl chloride is inaccurately indicated by some probes to receive nucleophilic solvent assistance because the model system (1-adamantyl chloride) has a different susceptibility to solvent electrophilicity. Kevill and coworkers disagree with this proposal, noting that essentially the same tert-butyl to 1-adamantyl rate ratio is found for the chlorides and the sulfonium salts if solvent electrophilicity were important in one case but not the other, then the rate ratio should vary. 

Figure 1. A typical nonlinear EtOH-TFE plot. Here the substrate indicated to react with NSA is CH3SCH2CH2Cl, II (6). Rates are in reciprocal seconds and are relative rates for 1-adamantyl chloride. In solvent abbreviations, for example, 97T represents 97% aqueous trifluoroethanol, 95E represents 95% aqueous ethanol, and 70A represents 70% aqueous acetone, and so on.

Figure 2. Correlation of logarithms of solvolysis rates for 1-adamantyl chloride versus tert-butyl chloride at 25 °C (7). E represents ethanol, T represents trifluoroethanol, and HF represents hexafluoro-2-propanoL...

A mixture of 1-adamantyl alcohol, aq. 50%-NaOH-soln., and a little benzyltriethyl-ammonium chloride emulsified at 40° by vigorous stirring, chloroform added drop-wise during 2 hrs., and stirring continued 2 hrs. 1-adamantyl chloride. Y ... 

Gajewski, J.J., Is the tert butyl chloride solvolysis the most misunderstood reaction in organic chemistry Evidence against nucleophihc solvent participation in the tert butyl chloride transition state and for increased hydrogen bond donation to the 1 adamantyl chloride solvolysis transition state, /. Am. Chem. Soc., 2001, 123(44), 10877-10883. 

Chlorination of adamantane by carbon tetrachloride is catalyzed by the Fe(III)-doped K-10 clays.Good yields of 1-adamantyl chloride and of 1,3-adamantyl dichloride were obtained. The intermediacy of a tertiary 1-adamantyl cation is postulated as in the following scheme. 

Sasaki, T. Usuki, A. Ohno, M. Synthesis of Adamantane Derivatives 49. Substitution Reaction of 1-Adamantyl Chloride with Some Trimethylsilylated Unsaturated Compounds. J.Org. Chem., 1980 vol. 45, 3559-3564. 

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