Solvolysis of alkyl diazotates. IV. Fate of the cyclopropylcarbinyl cation in aqueous base

Moss, Robert A.; Shulman, Franklyn C.; Emery, E. M.

doi:10.1021/ja01012a071

Cited by 6 publications

(4 citation statements)

References 2 publications

(2 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…When the fragmentation of 9 occurs in ethanol, we obtain 49% of chlorides 10 − 12 with a high 10 / 11 distribution (8.4), as well as 51% of the ethyl ether analogues of 10 − 12 with a much reduced cyclopropylcarbinyl/ cyclobutyl distribution (1.3). The chloride products represent ion pair return (probably from a “cis” ion pair analogous to 8 ), whereas the ether products most likely derive from solvolysis of a “trans” ion pair, or an ethanol-solvated (escaped) cyclopropylmethyl cation; the cyclopropylcarbinyl/cyclobutyl ratio is now very similar to the distribution obtained from the “free” cyclopropylmethyl cations formed in the nitrous acid deamination of cyclopropylmethylamine 14,16 or the hydrolysis of cyclopropylmethyl diazotate …”

Section: Cyclopropylmethoxychlorocarbenementioning

confidence: 70%

“…The chloride products represent ion pair return (probably from a "cis" ion pair analogous to 8), whereas the ether products most likely derive from solvolysis of a "trans" ion pair, or an ethanol-solvated (escaped) cyclopropylmethyl cation; the cyclopropylcarbinyl/cyclobutyl ratio is now very similar to the distribution obtained from the "free" cyclopropylmethyl cations formed in the nitrous acid deamination of cyclopropylmethylamine 14,16 or the hydrolysis of cyclopropylmethyl diazotate. 18…”

Section: Cyclopropylmethoxychlorocarbenementioning

confidence: 99%

See 1 more Smart Citation

The Fragmentation of Alkoxyhalocarbenes

Moss

1999

Acc. Chem. Res.

Self Cite

View full text Add to dashboard Cite

Alkoxyhalocarbenes stand at an intersection of carbene, carbocation, elimination, and substitution chemistry. Their fates are decided by several fundamental mechanisms, and we can anticipate significant contributions to mechanistic organic chemistry from an understanding of their behavior. In the 1950s, Hine 1 and Skell 2 reported that dihalocarbenes reacted with alkoxides to form alkoxyhalocarbenes, 1, and Skell suggested that, when sec-or tert-alcohols were used, the derived carbenes fragmented to alkyl cations with the loss of CO and X -(eq 1, X ) Cl or Br). Noting the close resemblance between CO and N 2 , Skell offered an analogy between reaction 1 and the decomposition of alkyldiazonium ions (RN 2 + f R + + N 2 ).

show abstract

Section: Cyclopropylmethoxychlorocarbenementioning

confidence: 70%

Section: Cyclopropylmethoxychlorocarbenementioning

confidence: 99%

The Fragmentation of Alkoxyhalocarbenes

Moss

1999

Acc. Chem. Res.

Self Cite

View full text Add to dashboard Cite

show abstract

“…under one of three sets of conditions (Scheme ): (1) in the presence of a kinetic nucleophilic trap, (2) in the presence of a reversible nucleophilic trap, or (3) under long-lived stable ion conditions. Under condition (1), CyC 4 + is rapidly trapped to form a mixture of cyclopropylmethyl, cyclobutyl, and 3-buten-1-yl products. , The product distribution depends on experimental conditions, but 3-buten-1-yl products are always the least abundant. Under condition (2), best exemplified by the acid-promoted rearrangement of aqueous cyclopropylmethanol, the distribution of products is determined by relative thermodynamic stability .…”

Section: Discussionmentioning

confidence: 99%

Cyclopropylmethyl/Cyclobutyl Rearrangements on Surfaces: Evidence for Transient Cation Formation near O-Covered Mo(110)

et al. 2007

View full text Add to dashboard Cite

Rearrangement reactions of C4-alkoxides on O-covered Mo(110) have been studied using temperature-programmed reaction spectroscopy and reflection-absorption infrared spectroscopy. Cyclobutoxide on Mo(110), prepared from the corresponding alcohol or bromide, is described for the first time in detail. Several reaction mechanisms are considered for the ring-opening rearrangement of cyclopropylmethoxide during high-temperature annealing. In light of compelling new data, previous results are reinterpreted to support the formation of transient cations near O-covered Mo(110). For the first time, we present strong evidence for clean, heterolytic bond cleavage reactions over a metal surface. Our revised reactivity model is based on spectroscopic and reactivity data that show the rearrangement of cyclopropylmethyl groups to cyclobutyl groups and vice versa. Selectively deuterated 1,1-D2-cyclopropylmethanol was studied as a test of mechanism and as a probe for the lifetime of reactive intermediates. Isotopic scrambling observed for this substrate is consistent with the formation of a relatively long-lived carbocation during rearrangement. The intermediacy of transient cations is further invoked to explain the rearrangements that are now recognized to occur as alkyl bromides are transformed into alkoxides on Mo(110)-(1 x 6)-O. The observed ring expansion/contraction reactions are characteristic of a cationic process; carbon-centered radicals are not known to rearrange in this manner. However, in none of the cases discussed could contributions from radical pathways be completely ruled out. Our results are compared to analogous reactions in the vapor and solution phases. General trends governing rearrangement mechanisms on Mo(110) are presented with respect to metal-surface coverage, heteroatom incorporation, and temperature. Trends are discussed in the context of heterogeneous hydrocarbon oxidation.

show abstract

“…With a more stable cation, e.g., cyclopropylcarbinyl, escape to hydrated carbonium ions is facilitated: hydrolysis of 1 (R = c-C3H5CH2) with H2180 gives cyclopropylcarbinol and cyclobutanol with, respectively, 11.9 and 14.7% return of the original 160. 41 This compares with 27% return for R = 2-octyl. A complete merging of HÑO2 deamination and diazotate hydrolysis was not observed in the cyclopropylcarbinyl system.…”

Section: Ihorfmentioning

confidence: 95%

Chemistry of alkanediazotates

Moss¹

1974

Acc. Chem. Res.

Self Cite

View full text Add to dashboard Cite

Alkanediazotates 42 1Schleyer's group at Princeton.38 In this case, l-adamantylcarbene ring-expands to 3-homoadamantene (24). The structure of 24 was inferred from the formation of appropriate dimers.Most of the experimental skill and m u c h of the conceptual input for the work just described were provided by a n exceptionally skilled group of young coworkers. Drs. William Baron, Mark D e c a m p , Michael Hendrick, and Ronald Levin all did portions of (38) M. Farcasiu, D. Farcasiu, R. T . Conlin, M. Jones, Jr., and P. v. R. Schleyer, J . Amer. Chem. Soc., 95,8207 (1973). this work as part of their Ph.D. Theses at Princeton. Dave Richardson's A . B . Thesis concerned the gas-phase pyrolysis of diazomalonic ester and T o m Berdick successfully worked out the formation of xylenes f r o m 16. Dr. V. V. Kane was instrumental i n making the synthetic efforts feasible, and Dr. Anthony Wolf carried out the paracyclophane and bridgehead olefin isolations and labeling experiments with great skill.

show abstract

Solvolysis of alkyl diazotates. IV. Fate of the cyclopropylcarbinyl cation in aqueous base

Cited by 6 publications

References 2 publications

The Fragmentation of Alkoxyhalocarbenes

The Fragmentation of Alkoxyhalocarbenes

Cyclopropylmethyl/Cyclobutyl Rearrangements on Surfaces: Evidence for Transient Cation Formation near O-Covered Mo(110)

Chemistry of alkanediazotates

Contact Info

Product

Resources

About