Diels–Alder reactions of 4,4-dimethyl-2-cyclohexenones. A direct route to the 4,4-dimethyl-1-decalones

Liu, Hsing‐Jang; Browne, E. N. C.

doi:10.1139/v87-214

Cited by 22 publications

(25 citation statements)

References 39 publications

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“…Cycloadditions and structural assignments It is known that the Diels-Alder reaction with a 2-substituted diene can lead to a mixture of regioisomers (49), and complete orientational reversal in violation of the para rule has been observed (51,52). We wished to prove conclusively that the addition of dienyl phosphate 1 to ethyl vinyl ketone (Entry 1) gave para-addition product 8 and not regioisomer 30.…”

Section: Resultsmentioning

confidence: 96%

“…rules of Diels-Alder addition (45,(48)(49)(50)(51) were followed. The results are summarized in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…When the dienone ester 14 (51)(52)(53) was treated with diene 1 in the presence of stannic chloride at 0°C (Entry 6) the cycloaddition reaction proceeded slowly. After 65 h it gave an inseparable 9:2 mixture of two isomeric adducts in 23% yield.…”

Section: Resultsmentioning

confidence: 99%

“…In general the Diels-Alder additions of 2 proceeded in good to excellent yield with small excesses of the diene. As with 1 the usual orientational and stereochemical rules (45,48,49), particularly thepara rule (5 1, 52) and endo rule (32,51,57), were followed with a very high degree of selectivity. The structures of the adducts of 2 were unambiguously assigned on the basis of their spectral data including 'H nrnr decoupling experiments.…”

Section: Diels-alder Reactions Of Trans-2-diethylphosphoryloxy-13-mentioning

confidence: 94%

“…Diene 2 was prepared according to the published procedure (3 1). Lithium iodide dihydrate -collidine reagent was prepared as previously reported (51). Dienone ester 14 was prepared according to the published procedure (52,53).…”

Section: Methodsmentioning

confidence: 99%

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Lewis acid catalyzed Diels–Alder reactions of two useful dienyl phosphate esters

Liu¹,

Feng²,

Kim³

et al. 1994

Can. J. Chem.

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. The Lewis acid catalyzed Diels-Alder reactions of dienyl phosphate esters 1 and 2 were examined. 2-Diethylphosphoryloxy-1,3-butadiene (1) was found to react with a variety of a$-unsaturated carbonyl compounds under Lewis acid catalysis with excellent regioselectivity to give synthetically useful cyclohexene derivatives. The adducts were produced in accordance with the normal rules governing the Diels-Alder addition. In the presence of stannic chloride acyclic a$-unsaturated ketones such as ethyl vinyl ketone and methyl vinyl ketone reacted rapidly with diene phosphate 1 to give exclusively thepara-addition products 8 and 9 in excellent yields. When diene 1 was treated with the complex cyclic enone ester 14 in the presence of ferric chloride the single para-rule adduct 15 was obtained in good yield. The stannic chloride catalyzed Diels-Alder reactions of trans-2-diethylphosphoryloxy-l,3-pentadiene (2) were also studied. Diene phosphate 2 reacted efficiently with a number of acyclic a$-unsaturated ketones such as methyl vinyl ketone, ethyl vinyl ketone, and trans-3-penten-2-one with complete regio-and stereoselectivity to give single cyclohexene derivatives 38,39, and 40.HSWG-JANG Lnr, WAISENG MARTIN FENG, JEUNG BEA KIM et ERIC N.C. BROWNE. Can. J. Chem. 72,2163Chem. 72, (1994. On a ttudit les rtactions de Diels-Alder catalystes par les acides de Lewis des esters 1 et 2, phosphates de ditnyle. On a trouvt que, sous catalyse par les acides de Lewis, le 2-diithylphosphoryloxybuta-1,3-dibne (1) rtagit avec une varittt de composts carbonylts ol$-insaturts avec une excellent rtgiostlectivitt pour conduire B des dtrivts du cyclohexbne qui sont utiles en synthbse. Les adduits se produisent selon les rbgles normales gouvernant les additions de Diels-Alder. En prtsence de chlorure stannique, les cttones u,p-insaturtes, telles que l'tthyl vinyl cttone et la mtthyl vinyl cttone, rtagissent rapidement avec le phosphate ditnique 1 pour donner exclusivement les produits d'additionpara, 8 et 9, avec d'excellents rendements. Lorsqu'on traite le dibne 1 avec l'ester cyclohextnonique complexe 14, en prisence de chlorure ferrique, seul l'adduit para, 15, a ttt obtenu avec un bon rendement. On a aussi ttudit les rtactions de Diels-Alder catalystes par le chlorure stannique du trans-2-ditthylphosphoryloxybuta-1,3-dibne (2). Le phosphate diinique 2 rtagit d'une f a~o n efficace avec un certain nombre de cttones a,p-insaturtes, telles que la mtthyl vinyl cttone, l'tthyl vinyl cttone et la trans-pent-3-tn-2-one, avec des rtgio-et sttrtostlectivitts complbtes pour donner uniquement les dtrivts cyclohextniques 38,39 et 40.[Traduit par la rtdaction]

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Section: Resultsmentioning

confidence: 96%

“…rules of Diels-Alder addition (45,(48)(49)(50)(51) were followed. The results are summarized in Table 1.…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Diels-alder Reactions Of Trans-2-diethylphosphoryloxy-13-mentioning

confidence: 94%

Section: Methodsmentioning

confidence: 99%

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Lewis acid catalyzed Diels–Alder reactions of two useful dienyl phosphate esters

Liu¹,

Feng²,

Kim³

et al. 1994

Can. J. Chem.

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1,3-Pentadiene

Zhong

Rawal

2001

Encyclopedia of Reagents for Organic Synthesis

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The Krapcho Dealkoxycarbonylation Reaction of Esters with α‐Electron‐Withdrawing Substituents

Krapcho

Ciganek

2013

Organic Reactions

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The Krapcho reaction involves esters with α‐electron‐withdrawing substituents such as malonates, β‐keto esters, and α‐cyano esters, which undergo dealkoxycarbonylation on being heated in polar aprotic solvents (such as DMSO, DMF, or HMPT) in the presence of water, or in polar aprotic solvents with water in the presence of added salts (such as NaCN, NaCl, LiCl, LiI, or MgCl 2 ). This procedure avoids the use of strongly aqueous acidic and alkaline conditions and tolerates many functional and protecting groups. The chapter presents the mechanistic aspects of this procedure, which include reaction parameters such as solvents, salts, other additives, and the use of microwave irradiation. The diastereoselectivity of protonation of the enolate intermediate leading to the dealkoxycarbonylated products is discussed. Trapping of the intermediate enolate by electrophiles other than a proton is illustrated. Potential side reactions and same‐pot subsequent reactions of substrates are discussed along with functional‐group compatibility for halogens and nitrogen, oxygen, sulfur, selenium, and carbon functional groups. Several examples of applications of this methodology for the synthesis of natural products along with experimental conditions and procedures are presented. Closely related methods are discussed in the Comparison with Other Methods section. The tables, which consist of 371 pages, are grouped according to substrate structure. Selective entries for other methods (excluding classical aqueous acidic or basic methods) are included in the tabular survey for comparative purposes.

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Diels–Alder reactions of 4,4-dimethyl-2-cyclohexenones. A direct route to the 4,4-dimethyl-1-decalones

Cited by 22 publications

References 39 publications

Lewis acid catalyzed Diels–Alder reactions of two useful dienyl phosphate esters

Lewis acid catalyzed Diels–Alder reactions of two useful dienyl phosphate esters

1,3-Pentadiene

The Krapcho Dealkoxycarbonylation Reaction of Esters with α‐Electron‐Withdrawing Substituents

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