Synthesis And Novel Stereochemical Results In The Lithium–Ammonia Reduction Of Some 4-Alkyl-Δ<sup>1(9)</sup>-2-octalones

Piers, Edward; Phillips-Johnson, Wynona M.; Berger, Christian

doi:10.1139/v75-177

Cited by 8 publications

(6 citation statements)

References 17 publications

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“…The question as to which pathway should be preferred may be addressed on the basis of proposals originally set forth by Robinson (17) (see also ref. 18). …”

Section: Results and Discussion ( A ) Preparation Of The Tricyclic Enmentioning

confidence: 99%

Total synthesis of amphilectane-type diterpenoids: (±)-8,15-diisocyano-11(20)-amphilectene

Piers¹,

Llinàs‐Brunet²,

Oballa³

1993

Can. J. Chem.

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EDWARD PIERS, MONTSE LLINAS-BRUNET, and RENATA M. OBALLA. Can. J. Chem. 71, 1484Chem. 71, (1993 A total synthesis of the structurally novel, antimicrobial diterpenoid ("1-8,15-diisocyano-l l(20)-amphilectene (2) is described. Alkylation of 2-methoxycarbonyl-3-methylcyclohexanone (13) with (E)-I-(tert-buty1dimethylsiloxy)-6-iodo-3-(trimethylstanny1)-2-hexene (14) provided, stereoselectively, the functionalized keto ester 15, which was converted efficiently into the diene 17. Diels-Alder reaction of 17 with acrolein, followed by base-catalyzed equilibration of the resultant product mixture, gave the aldehydes 19 (58%) and 20 (29%). Allylic oxidation of the alkene 24 (derived from 19) afforded the enone 25. Reduction (Na, NH,, t-BuOH) of 25 gave 28, which was converted, via a sequence of eight synthetic steps, into the diacid 45. Efficient transformation of the carboxyl functions of 45 into isonitrile groups completed the synthesis of (* 1-2.EDWARD PIERS, MONTSE LLINAS-BRUNET et RENATA M. OBALLA. Can. J. Chem. 71, 1484Chem. 71, (1993. On dtcrit une synthitse totale du diterptne antimicrobien, (5)-8,15-diisocyanoamphilect-1 l(20)-itne (2) qui est structuralement nouveau. L'alkylation de la 2-mtthoxycarbonyl-3-mCthylcyclohexanone (13) avec le (Ej-1-(tert-butyldimCthylsiloxy)-6-iodo-3-(trimCthylstannyl)hex-2-ene (14) permet d'acceder sttrtoselectivement au cttoester fonctionnalist 15, que l'on transforme efficacement en un diitne 17. La reaction de Diels-Alder du compose 17 avec I'acroltine, suivie de l'kquilibration catalyste par une base du melange de produits resultant, donne les aldehydes 19 (58%) et 20 (29%). L'oxydation allylique de l'alckne 24 (dtrivt du compost 19) fournit l'enone 25. La rtduction (par Na, NH,, t-BuOH) du compose 25 conduit au compost 28 qui, par une synthkse h huit ttapes, donne le diacide 45. La transformation efficace des fonctions carboxyles du compost 45 en groupes isonitriles complkte la synthkse du compost (5)-2.[Traduit par la rtdaction]

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“…The question as to which pathway should be preferred may be addressed on the basis of proposals originally set forth by Robinson (17) (see also ref. 18). …”

Section: Results and Discussion ( A ) Preparation Of The Tricyclic Enmentioning

confidence: 99%

Total synthesis of amphilectane-type diterpenoids: (±)-8,15-diisocyano-11(20)-amphilectene

Piers¹,

Llinàs‐Brunet²,

Oballa³

1993

Can. J. Chem.

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“…Routine i.r. spectra 6This general section is applicable to the succeeding, accompanying paper (13), as well as to the present paper.…”

Section: General6mentioning

confidence: 89%

“…Therefore, the steroselective formation of the cis-fused decalone 16 lithium-ammonia reduction of octalone 13 was initially surprising and clearly seemed to suggest that the presence of an axially-oriented substituent at the C , position of A1'9'-2-octalones can exert a profound effect on the stereochemical outcome of the reduction. A more detailed study and discussion of this observation can be found in the accompanying paper (13).…”

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confidence: 83%

A Synthetic Approach To Cadinane- and Amorphane-Type Sesquiterpenoids via Annelation Of Cyclohexanone Derivatives With (E)-2-Methyl-3-hepten-5-one. A Simple Synthesis of (±)-Cadinene Dihydrochloride

Piers¹,

Phillips-Johnson²

1975

Can. J. Chem.

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EDWARD PIERS and WYNONA M. PHILLTPS-JOHNSON. Can. J. Chem. 53, 1281Chem. 53, (1975. The annelation of the pyrrolidine enamine of cyclohexanone with (E)-2-methyl-3-hepten-5-one (7) afforded a 7:3 mixture of the octalones 12 and 13. Lithium-ammonia reduction of the former afforded the trans-fused decalone 14, whereas, in contrast, a similar reduction of 13 gave exclusively the cis-fused decalone 16. Annelation of the pyrrolidine enamine of Chydroxycyclohexanone with the unsaturated ketone 7 yielded a 7: 3 mixture of the octalones 22 and 23. The former was converted via a short, efficient synthetic sequence into (+)-cadinene dihydrochloride (30).EDWARD PIERS et WYNONA M. PHILLIPS-JOHNSON. Can. J. Chem. 53, 1281Chem. 53, (1975.L'Bnamine derivant de la pyrrolidine et de la cyclohexanone soumise a une reaction d'annelation avec la methyl-2 heptkne-3 one-5 (E) (7) conduit a un melange 7:3 des octalones 12 et 13. La reduction par le lithium dans I'ammoniac de 12 conduit a la decalone trans 14 alors qu'une reduction similaire de 13 conduit uniquement a la d h l o n e cis (16). L'knamine derivk de la The fairly large number of sesquiterpenoids which possess the basic carbon skeleton as shown in 1' have by convention been divided into four classes or subgroups, differing only in the relative stereochemistry at C,, C,, and C, (1,2). Thus, the cadinane-type (2) and bulgaranetype (3) sesquiterpenoids possess trans-fused six-membered rings and differ only in the relative stereochemical orientation of the isopropyl or related side chain. On the other hand, in the muurolanes (4) and the amorphanes (5), the decalin systems are cis-fused. Again, these two types differ only in the relative stereochemistry at C,.The four sesquiterpenoid classes mentioned above are constituted mainly of olefinic hydrocarbons and alcohols. Structurally speaking, many of the individual members of these classes are very closely related and often differ from one another only in the position of an olefinic double bond and/or in a diastereomeric sense. Because of this, it has often been difficult to separate mixtures of these types of compounds into individual components, and the structural 'The numbering system shown in structure 1 is that normally used for the cadinane and related sesquiterpenoids.and stereochemical elucidation of the cadinane and related sesquiterpenoids was, in the past, often carried out with impure materials. Consequently, the chemical literature dealing with this area contains many conflicting and erroneous reports. A classic and, perhaps, extreme example of this involves the naturally occurring olefinic alcohol 6-cadinol. Since its isolation in 1922, no fewer than seven different proposals have been put forward regarding the structure and sterochemistry of this compound, the latest (3) being that 6-cadinol is actually a muurolane derivative. Can. J. Chem. Downloaded from www.nrcresearchpress.com by 54.149.104.195 on 05/09/18For personal use only.

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“…In 1974, Piers was investigating lithium-ammonia reductions of various octalone systems. 9 These reactions generated the isomeric cis-and trans-products in unequal proportions. He required access to pure and authentic samples of each stereoisomer in order to properly evaluate his results.…”

Section: Figure 1 Compounds Possessing Termiticidal Activity Againstmentioning

confidence: 99%

“…However, in contrast to Augustine's findings, cis-fused products are preferred under basic media, and acidic media yields preferentially the trans-isomer. [7][8][9] In the early 1980s, Crabtree demonstrated that the iridium catalyst, [Ir(cod)py(PCy 3 )]PF 6 , was effective in the stereoselective hydrogenation of cyclic allylic alcohols. [10][11][12][13] It is precedented that the addition of hydrogen to the neighboring alkene occurs syn to the directing hydroxy group.…”

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confidence: 99%

Hydrogenation Selectivity of the Bicyclo[4.4.0]decane Ring System of Valencanes

Sauer¹,

Crowe²,

Henderson³

et al. 2010

Synlett

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Synthesis And Novel Stereochemical Results In The Lithium–Ammonia Reduction Of Some 4-Alkyl-Δ¹⁽⁹⁾-2-octalones

Cited by 8 publications

References 17 publications

Total synthesis of amphilectane-type diterpenoids: (±)-8,15-diisocyano-11(20)-amphilectene

Total synthesis of amphilectane-type diterpenoids: (±)-8,15-diisocyano-11(20)-amphilectene

A Synthetic Approach To Cadinane- and Amorphane-Type Sesquiterpenoids via Annelation Of Cyclohexanone Derivatives With (E)-2-Methyl-3-hepten-5-one. A Simple Synthesis of (±)-Cadinene Dihydrochloride

Hydrogenation Selectivity of the Bicyclo[4.4.0]decane Ring System of Valencanes

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Synthesis And Novel Stereochemical Results In The Lithium–Ammonia Reduction Of Some 4-Alkyl-Δ1(9)-2-octalones

Cited by 8 publications

References 17 publications

Total synthesis of amphilectane-type diterpenoids: (±)-8,15-diisocyano-11(20)-amphilectene

Total synthesis of amphilectane-type diterpenoids: (±)-8,15-diisocyano-11(20)-amphilectene

A Synthetic Approach To Cadinane- and Amorphane-Type Sesquiterpenoids via Annelation Of Cyclohexanone Derivatives With (E)-2-Methyl-3-hepten-5-one. A Simple Synthesis of (±)-Cadinene Dihydrochloride

Hydrogenation Selectivity of the Bicyclo[4.4.0]decane Ring System of Valencanes

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Synthesis And Novel Stereochemical Results In The Lithium–Ammonia Reduction Of Some 4-Alkyl-Δ¹⁽⁹⁾-2-octalones