New stereoselective synthesis of 9-methyl-cis-decalin derivatives by double Michael reaction of 3-methyl-4-methylenecyclohex-2-enone and its congeners with dimethyl 3-oxoglutarate

Irie, Hiroshi; Mizuno, Yukio; Taga, Tooru; Osaki, Kunihiro

doi:10.1039/p19820000025

Cited by 9 publications

(1 citation statement)

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“…Many sesquiterpenes possessing a furan ring have been isolated from plant species and among them, the furanoeremophilanes, (I), are the most abundant (Hikino & Konno, 1976;Kuroyanagi et al, 1985;Torres et al, 1999). The interesting linearly fused furo [2,3-b]decalin framework, containing syn-vicinal dimethyl groups at atoms C-4a and C-5, of these compounds, together with the biological activities shown by some of them, have attracted the attention of many synthetic chemists (Irie et al, 1982;Jacobi et al, 1984;Koike et al, 1999;Miyashita et al, 1980;Tada et al, 1980;Yamakawa et al, 1983). We have designed a strategy for the synthesis of the basic skeleton (I), in which the key step is the preparation of compounds such as the ketol (II).…”

Section: Commentmentioning

confidence: 99%

2-[3-Furyl(hydroxy)methyl]-2,3-dimethylcyclohexanone

García

Mendoza

et al. 2002

Acta Crystallogr C

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Contribution No. 1750 of the Instituto de Quimica, UNAM, Mexico. In the molecule of the title compound, C(13)H(18)O(3), there is a syn relationship between the two vicinal methyl groups. The six-membered ring adopts a chair conformation, with one equatorial and two axial groups, and the furyl group is almost parallel to the ketone group. Intermolecular hydrogen bonds [O[bond]H...O[double bond]C 2.814 (3) A] form chains along [100].

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Section: Commentmentioning

confidence: 99%

2-[3-Furyl(hydroxy)methyl]-2,3-dimethylcyclohexanone

García

Mendoza

et al. 2002

Acta Crystallogr C

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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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