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

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.

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A Vinyl Radical Cyclization Route to Hydroxycyclohexene Fused Carbocycles

Asian Journal of Chemistry ◽

10.14233/ajchem.2016.19465 ◽

2016 ◽

Vol 28 (1) ◽

pp. 233-234 ◽

Cited By ~ 1

Author(s):

Shiladitya Chaudhuri ◽

Susama Maity ◽

Mahua Roy ◽

Paramita Ray ◽

Jayanta K. Ray

Keyword(s):

Radical Cyclization ◽

Vinyl Radical

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Preparation of optically active bicyclodihydrosiloles by a radical cascade reaction

Beilstein Journal of Organic Chemistry ◽

10.3762/bjoc.9.149 ◽

2013 ◽

Vol 9 ◽

pp. 1326-1332 ◽

Cited By ~ 6

Author(s):

Koichiro Miyazaki ◽

Yu Yamane ◽

Ryuichiro Yo ◽

Hidemitsu Uno ◽

Akio Kamimura

Keyword(s):

Silicon Atom ◽

Cascade Reaction ◽

Radical Cyclization ◽

Optically Active ◽

Unsaturated Ester ◽

Terminal Alkyne ◽

Silyl Radical ◽

Vinyl Radical ◽

Radical Cascade ◽

Carbonyl Radical

Bicyclodihydrosiloles were readily prepared from optically active enyne compounds by a radical cascade reaction triggered by tris(trimethylsilyl)silane ((Me3Si)3SiH). The reaction was initiated by the addition of a silyl radical to an α,β-unsaturated ester, forming an α-carbonyl radical that underwent radical cyclization to a terminal alkyne unit. The resulting vinyl radical attacked the silicon atom in an SHi manner to give dihydrosilole. The reaction preferentially formed trans isomers of bicyclosiloles with an approximately 7:3 to 9:1 selectivity.

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Vinyl radical cyclization onto imino group. Selective 6-endo cyclization onto aldimines leading to 3-methylenepiperidines

Tetrahedron Letters ◽

10.1016/s0040-4039(98)02666-5 ◽

1999 ◽

Vol 40 (8) ◽

pp. 1515-1518 ◽

Cited By ~ 26

Author(s):

Ilhyong Ryu ◽

Shin-ichi Ogura ◽

Satoshi Minakata ◽

Mitsuo Komatsu

Keyword(s):

Radical Cyclization ◽

Imino Group ◽

Vinyl Radical

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Seven-Membered Ring Formation through a Robinson Annulation

Category 6, Compounds with All-Carbon Functions ◽

10.1055/sos-sd-045-01169 ◽

2010 ◽

pp. 1

Author(s):

K. Abou-Hadeed ◽

H.-J. Hansen

Keyword(s):

Membered Ring ◽

Ring Formation ◽

Robinson Annulation

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

Synthesis ◽

10.1055/s-0039-1690693 ◽

2019 ◽

Vol 52 (08) ◽

pp. 1231-1238 ◽

Cited By ~ 2

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.

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