The effect of C-3 spirocyclopropyl substitution on solvolysis of epimeric, tertiary 2-methyl-2-benzonorbornenyl- and 2-methyl-2-norbornyl-P-nitrobenzoates

Lenoir, Dieter; Roll, William D.; Ipaktschi, Junes

doi:10.1016/0040-4039(76)80073-1

Cited by 7 publications

(2 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The rates of solvolysis in 70% acetone−water of exo - and endo -spiro[cyclopropane-1,3‘-norbornan]-2‘-yl 3,5-dinitrobenzoates 6 (Figure ) are strikingly similar, showing little of the large exo / endo rate ratio associated with the 2-norbornyl system . Also interesting is the ca.…”

Section: Introductionmentioning

confidence: 90%

An Experimental and Computational Study about the Effect of a Spirocyclopropane Group on the Solvolysis Rates of Bridgehead Triflates

Cerero

et al. 1999

J. Org. Chem.

View full text Add to dashboard Cite

7',7'-Dimethylspiro[cyclopropane-1,2'-norbornan]-1'-yl triflate (9) was obtained and its solvolysis rates in buffered 60% aqueous ethanol were determined at different temperatures. The solvolytic behavior of 9 and other bridgehead derivatives (13-17, see Table 1) was studied by force-field, semiempirical and ab initio [B3LYP/6-31g(d)] methods. Cation 9(+) is a slightly pyramidal cyclopropylcarbinyl cation in a nearly perpendicular conformation, showing an sp(2)-like hybridization. Its high electron demand provokes an enhancement of the sigma-participation of the C(5)-C(6) and C(4)-C(7) bonds. The introduction of a cyclopropyl group adjacent to the bridgehead cation leads to an increase of the strain energy. This fact has two opposite effects on the solvolysis rate: (a) the strain energy hinders the flattening of the cation and, hence, originates a rate depression, and (b) the strained C-C bonds are prone to stabilize the cation at C(1) by sigma-delocalization, which provokes a rise of the solvolysis rate. Both effects are accounted for only by the B3LYP/6-31g method. The claimed electron-withdrawal effect of the cyclopropyl group as a basis for the small k(17)/k(16) rate ratio is not confirmed by our calculations.

show abstract

Section: Introductionmentioning

confidence: 90%

An Experimental and Computational Study about the Effect of a Spirocyclopropane Group on the Solvolysis Rates of Bridgehead Triflates

Cerero

et al. 1999

J. Org. Chem.

View full text Add to dashboard Cite

show abstract

“…Ein besonders anregendes Buch, wenn man es als einen Beitrag zur Erkenntnistheorie von mechanistischen Betrachtungen in der organischen Chemie auffaljt. H. C. Brown weist nach, dalj sich die Befunde von Winstein prinzipiell auch auf andere Weise deuten lassen, als Winstein es getan hat: Statt eines verbruckten Ions kann man ein sich sehr schnell einstellendes Gleichgewicht zwischen den entarteten klassischen Kationen (5) und (5') annehmen; die unterschiedliche Reaktivitat der isomeren Sulfonate sowie die exo-Stereospezifitat kann man auch durch steri sche Effekte deuten, namlich durch die sterische Behinderung bei der Ionisation der Austrittsgruppe der endo-Verbindung (4). Das Gleichgewicht (5) 2 (5') mu13 sich rnit nahezu diffusionskontrollierter Geschwindigkeit einstellen, bevor die Kationen rnit dem Losungs-mittel abreagieren.…”

unclassified

Die Kontroverse über nicht‐klassische Carbonium‐Ionen

Lenoir¹

1978

Nachr. Chem. Tech. Lab.

View full text Add to dashboard Cite

Long‐Lived Cyclopropylcarbinyl Cations

Oláh¹,

Reddy²,

Prakash³

2009

Patai's Chemistry of Functional Groups

View full text Add to dashboard Cite

Introduction General Methods of Preparation of Long‐Lived Cyclopropylcarbinyl Cations Primary Cyclopropylcarbinyl Cations Secondary and Tertiary Cyclopropylcarbinyl Cations Spirocyclopropylcarbinyl Cations Cyclopropylcarbinyl Dications Extent of Positive Charge Delocalization into the Cyclopropyl Group X ‐Ray Crystallographic Studies Conclusions and Outlook

show abstract

The effect of C-3 spirocyclopropyl substitution on solvolysis of epimeric, tertiary 2-methyl-2-benzonorbornenyl- and 2-methyl-2-norbornyl-P-nitrobenzoates

Cited by 7 publications

References 13 publications

An Experimental and Computational Study about the Effect of a Spirocyclopropane Group on the Solvolysis Rates of Bridgehead Triflates

An Experimental and Computational Study about the Effect of a Spirocyclopropane Group on the Solvolysis Rates of Bridgehead Triflates

Die Kontroverse über nicht‐klassische Carbonium‐Ionen

Long‐Lived Cyclopropylcarbinyl Cations

Contact Info

Product

Resources

About