Carbon Atom Insertion: A One-Step Synthesis of Tricyclo[3.2.1.02,7]octanes and Tricyclo[4.1.0.02,7]heptanes from Cyclohexenes1

Cory, Robert M.; Burton, Lester P. J.; Pecherle, R. G.

doi:10.1080/00397917908064187

Cited by 9 publications

(3 citation statements)

References 6 publications

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“…That the C−H(D) insertion reaction indeed is not a “reliable criterium for carbene reactivity”, as supposed one year earlier,6b was independently proven by Kirmse and Wächtershäuser in 1966 14a. They compared the competition of the cyclopropane forming intramolecular C−H insertion reactions into tertiary (3°), secondary (2°), and primary (1°) C−H bonds of the carbenoids R-CHNaCl 16a − f , formed from the corresponding halides R-CH 2 Cl and NaNH 2 , with those of the carbenes R-CH 17a − f , prepared from the corresponding diazo species R-CH-N 2 .…”

Section: Carbenoidsmentioning

confidence: 91%

“…In the same publication,14a Kirmse and Wächtershäuser reported not only on C−H insertion reactions but also on 1,2-alkyl migrations of neo-alkyl-type carbenoids to give olefins. An example is given by the carbenoids 1-metallo-1-iodo-2,2,3-trimethylbutane 18 which on warming led not only to the cyclopropanes 19 and 20 (C−H insertion) but also to the olefins 21 and 22 (alkyl migration); see Scheme .…”

Section: Carbenoidsmentioning

confidence: 99%

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The Electrophilic Nature of Carbenoids, Nitrenoids, and Oxenoids

2001

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Section: Carbenoidsmentioning

confidence: 91%

Section: Carbenoidsmentioning

confidence: 99%

The Electrophilic Nature of Carbenoids, Nitrenoids, and Oxenoids

2001

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“…These yields were, even at this level of development, a significant improvement over the overall yields from the Moore two-step procedure (9% and 15%, respectively), but further increases were observed when a more dilute solution in diethyl ether was used, amounts of carbon tetrabromide and methyllithium were doubled, and the second addition of methyllithium was carried out at -30°C instead of 0°C. Under these optimum conditions (17) not only the total yield of carbon atom insertion products, but also the relative proportion of the desired tricyclooctane (24) were obtained in a combined yield of 80%, containing equal amounts of the two isomers. Thus our one-step method is, at least in this case, far superior to the Moore two-step sequence, being much more convenient and providing a greater than 300% enhancement in the yield of the ishwarane model compound, 24.…”

mentioning

confidence: 99%

Carbon atom insertion bicycloannulation: total syntheses of ishwarane and ishwarone

Cory¹,

Burton²,

Chan³

et al. 1984

Can. J. Chem.

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. Can. J. Chem. 62, 1908Chem. 62, (1984. insertion of a carbon atom into a methyl cyclohexene, leading in a single synthetic step to a bicyclo[3.2. I .02.']octane by carbene addition to the double bond and carbene insertion into a methyl C-H bond, has been accomplished by treating the cyclohexene with carbon tetrabromide and methyllithium at low temperatures. This new bicycloannulation method has been employed in a total synthesis of ishwarane (I), the naturally occurring parent hydrocarbon of the ishwarane class of tetracyclic sesquiterpenes. Although this reaction was not successful with various possible precursors of ishwarone (2), this natural product was prepared in low yield by a two-step version of the carbon atom insertion bicycloannulation (CAiB) procedure involving addition of bromoform-derived dibromocarbene to the octalone (5) followed by treatment of the resulting dibromocyclopropane (56) with methyllithiurn. The same two-step sequence was also successful in the first synthesis of norishwarane (20), the hydrocarbon comprising the bare ring system of the ishwarane sesquiterpenoids. The Diels-Alder synthesis used in the preparation of the octalin precursor (18) of norishwarane could not be used for the terpenes themselves because of the lack of dienophilic reactivity of the required cyclohexenone (7). A regioselective Diels-Alder equivalent sequence was therefore developed, consisting of conjugate addition of lithium di(3-methyl-3-buteny1)cuprate (42) to 2,3,4-trimethylcyclohex-Zen-I-one (7), epoxidation, base-catalyzed cyclization of the resulting epoxide (47) to a mixture of primary and tertiary alcohols (50 and 49, respectively), and dehydration of 49 to give 5. In the case of ishwarane, the octalin precursor (62) was synthesized by conjugate addition of lithium dimethylcuprate to octalone 59, addition of methyl magnesium bromide to the resulting decalone (60) to give octalol 61, and dehydration. Chem. 62, 1908Chem. 62, (1984.En faisant rkagir le cyclohexkne avec le titrabromure de carbone et le mCthyllithium a basse tempkrature, on a rtalisC I'insertion d'un atome de carbone dans le mCthylcyclohexkne; on a ainsi obtenu en une seule Ctape le bicyclo[3.2.1 .02.']octane par I'addition de carbene sur la double liaison et par une insertion de carbkne dans une liaison C-H du mithyle. OR a utilisee cette nouvelle methode de bicycloannellation dans une synthttse totale de I'ishwarane (I), I'hydrocarbure naturel parent des sesquiterpknes tetracycliques de la classe de I'ishwarane. Bien que cette reaction n'aie pas pu &tre appliquCe avec succes i divers precurseurs possibles de I'ishwarone (2), on a prepare ce produit naturel avec un faible rendement en faisant appel a une version en deux Ctapes de la mtthode de bicycloannellation par insertion d'un atome de carbone (BIAC) impliquant une addition d'un dibromocarbkne, provenant du bromoforme, sur I'octalone (51, puis une reaction du dibromocyclopropane (56) qui en rtsulte avec du mCthyllithium. On a aussi utilist cette mCthode avec succks pour realiser ...

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Tribromomethyllithium

Albizati

2001

Encyclopedia of Reagents for Organic Synthesis

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Carbon Atom Insertion: A One-Step Synthesis of Tricyclo[3.2.1.0^2,7]octanes and Tricyclo[4.1.0.0^2,7]heptanes from Cyclohexenes¹

Cited by 9 publications

References 6 publications

The Electrophilic Nature of Carbenoids, Nitrenoids, and Oxenoids

The Electrophilic Nature of Carbenoids, Nitrenoids, and Oxenoids

Carbon atom insertion bicycloannulation: total syntheses of ishwarane and ishwarone

Tribromomethyllithium

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