Ring formation via β-keto ester dianions

1977 ◽  
Vol 55 (6) ◽  
pp. 996-1000 ◽  
Author(s):  
Phaik-Eng Sum ◽  
Larry Weiler
Keyword(s):  
Membered Ring ◽  
Ring Formation ◽  
Methyl Acetoacetate ◽  
Keto Ester ◽  
Keto Esters

The reaction of α,ω-dihalides with the dianion of methyl acetoacetate gives a mixture of mono- and bisalkylated products. The monoalkylated products can be cyclized via the monoanion to cyclic β-keto esters with a seven- or eight-membered ring. Alternatively these monoalkylated products can be cyclized via the dianion to γ-cyclopentyl- or γ-cyclohexyl-β-keto esters.

Aldol Type Condensations of β-Keto Ester Dianions

1974 ◽  
Vol 52 (11) ◽  
pp. 2157-2164 ◽  
Author(s):  
Stuart Nicholas Huckin ◽  
Larry Weiler
Keyword(s):  
Conjugate Addition ◽  
Methyl Acetoacetate ◽  
Keto Ester ◽  
Unsaturated Ketones ◽  
Keto Esters ◽  
Hydroxy Esters ◽  
Carbonyl Addition

The dianion of methyl acetoacetate reacts with ketones and aldehydes to yield δ -hydroxy-β-keto esters. These hydroxy esters can be dehydrated to the corresponding γ,δ-unsaturated-β-keto esters which are useful in annelation reactions to form cyclic β-keto esters. The dianion of methyl acetoacetate does not appear to undergo conjugate addition to simple α,β-unsaturated ketones, instead only carbonyl addition occurs.

The Acylation of β-Keto Ester Dianions

1974 ◽  
Vol 52 (8) ◽  
pp. 1343-1351 ◽  
Author(s):  
Stuart Nicholas Huckin ◽  
Larry Weiler
Keyword(s):  
Methyl Acetoacetate ◽  
Keto Ester ◽  
Keto Esters

A method for the successful acylation of the dianion of simple β-keto esters to yield β,δ-diketo esters has been developed. The dianion of methyl acetoacetate also reacts with the monoanion of methyl acetoacetate to give a triketo ester which cyclizes to methyl orsellinate. These dianions also add to nitriles to give 5-amino-3-keto-4-pentenoates which may in some cases cyclize to 4-hydroxypyridones.

scholarly journals The enantioselective β-keto ester reductions by Saccharomyces cerevisiae

2006 ◽  
Vol 71 (8-9) ◽  
pp. 889-894 ◽  
Author(s):  
Nosrat Mahmoodi ◽  
Hassan Tajik ◽  
Khalil Tabatabaeian ◽  
Mahmood Shahbazi
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Calcium Phosphate ◽  
Potassium Dihydrogen Phosphate ◽  
Dihydrogen Phosphate ◽  
Ammonium Tartrate ◽  
Potassium Dihydrogen ◽  
Keto Ester ◽  
Keto Esters ◽  
Diammonium Salt ◽  
Hydroxy Esters

The enantioselective yeast reduction of aromatic ?-keto esters, by use of potassium dihydrogen phosphate, calcium phosphate (monobasic), magnesium sulfate and ammonium tartrate (diammonium salt) (10:1:1:50) in water at pH7 as a buffer for 72-120h with 45-90 % conversion to the corresponding aromatic ?-hydroxy esters was achieved by means of Saccharomyces cerevisiae.

Seven-Membered Ring Formation through a Robinson Annulation

2010 ◽  
pp. 1
Author(s):  
K. Abou-Hadeed ◽  
H.-J. Hansen
Keyword(s):  
Membered Ring ◽  
Ring Formation ◽  
Robinson Annulation

Annulation of Indoles with 1,n-Dibromoalkanes by a Pd(II)-Catalyzed and Norbornene-Mediated Reaction Cascade

Synthesis ◽  
2019 ◽  
Vol 52 (08) ◽  
pp. 1231-1238 ◽  
Author(s):  
Michael Henkel ◽  
Thorsten Bach
Keyword(s):  
Direct Synthesis ◽  
Membered Ring ◽  
Ring Formation ◽  
Cascade Process

Employing 1,3-dibromopropane, 1,4-dibromobutane, and 1,5-dibromopentane as biselectrophiles, the annulation of indoles was probed in the presence of PdCl2(MeCN)2 as a catalyst and norbornene as a transpositional ligand. Ring formation to a five-membered ring was observed at positions C2 and N, while annulation of a six-membered ring occurred at positions C2 and C3. The latter cascade process was successfully applied to the direct synthesis of 1,2,3,4-tetrahydrocarbazoles from indoles (11 examples, 31–68% yield). Seven-membered-ring annulation was feasible by an initial coupling at positon C2 followed by alkylation at C3.

Six- versus Five-Membered Ring Formation in Radical Cyclizations of 7-Bromo-Substituted Hexahydroindolinones

2004 ◽  
Vol 6 (6) ◽  
pp. 917-920 ◽  
Author(s):  
Paitoon Rashatasakhon ◽  
Ayse Daut Ozdemir ◽  
Jerremey Willis ◽  
Albert Padwa
Keyword(s):  
Membered Ring ◽  
Ring Formation ◽  
Radical Cyclizations

ChemInform Abstract: Five vs Six Membered Ring Formation in the Vinyl Radical Cyclization.

ChemInform ◽  
1987 ◽  
Vol 18 (8) ◽  
Author(s):  
G. STORK ◽  
R. JUN. MOOK
Keyword(s):  
Radical Cyclization ◽  
Membered Ring ◽  
Ring Formation ◽  
Vinyl Radical

ChemInform Abstract: Six-Membered Ring Formation with o-Phenylene-diphosphine.

ChemInform ◽  
1987 ◽  
Vol 18 (22) ◽  
Author(s):  
K. ISSLEIB ◽  
E. LEISSRING ◽  
H. SCHMIDT
Keyword(s):  
Membered Ring ◽  
Ring Formation

scholarly journals On-Surface Synthesis of Indenofluorene Polymers by Oxidative Five-Membered Ring Formation

2018 ◽  
Vol 140 (10) ◽  
pp. 3532-3536 ◽  
Author(s):  
Marco Di Giovannantonio ◽  
José I. Urgel ◽  
Uliana Beser ◽  
Aliaksandr V. Yakutovich ◽  
Jan Wilhelm ◽  
...  
Keyword(s):  
Membered Ring ◽  
Ring Formation

Eight-Membered Ring Formation via Olefin Insertion into a Carbon—Carbon Single Bond.

ChemInform ◽  
2004 ◽  
Vol 35 (47) ◽  
Author(s):  
Takanori Matsuda ◽  
Atsushi Fujimoto ◽  
Mitsuru Ishibashi ◽  
Masahiro Murakami
Keyword(s):  
Membered Ring ◽  
Ring Formation ◽  
Single Bond
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