Synthetic Studies on the Stemona Alkaloids; Stereochemical Course of PhSe+-Induced Seven-Membered Ring Formation

Synlett ◽  
1990 ◽  
Vol 1990 (05) ◽  
pp. 279-281 ◽  
Author(s):  
Li Xiang ◽  
Alan P. Kozikowski
Keyword(s):  
Membered Ring ◽  
Ring Formation ◽  
Synthetic Studies ◽  
Stemona Alkaloids

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.

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: 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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