Unravelling the stereoselectivity in 6-exo-trig radical cyclization of α,β-unsaturated ester-tethered sugars. A tale of two stereocenters

2010 ◽  
Vol 8 (7) ◽  
pp. 1619
Author(s):  
Marcelo T. de Oliveira ◽  
Amary Cesar ◽  
Daniel H. S. Leal ◽  
Maria A. F. Prado ◽  
Thais H. Á. da Silva ◽  
...  
Keyword(s):  
Radical Cyclization ◽  
Unsaturated Ester

scholarly journals Preparation of optically active bicyclodihydrosiloles by a radical cascade reaction

2013 ◽  
Vol 9 ◽  
pp. 1326-1332 ◽  
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.

Diastereofacial Selectivity of Radical Cyclization Using Chiral a,b-Unsaturated Ester and Amide: Investigation of a New Chiral Synthon Synthesis

Heterocycles ◽  
1997 ◽  
Vol 46 (1) ◽  
pp. 605 ◽  
Author(s):  
Masataka Ihara ◽  
Akira Katsumata ◽  
Takehiko Iwaki ◽  
Keiichiro Fukumoto
Keyword(s):  
Radical Cyclization ◽  
Unsaturated Ester ◽  
Chiral Synthon

Diastereoselective radical cyclization using a chiral α-methyl-α,β-unsaturated ester: Controlling the stereochemistry at both the α- and β-positions

1995 ◽  
Vol 6 (11) ◽  
pp. 2657-2660 ◽  
Author(s):  
Mayumi Nishida ◽  
Manami Nobura ◽  
Kazuyo Nakaoka ◽  
Atsushi Nishida ◽  
Norio Kawahara
Keyword(s):  
Radical Cyclization ◽  
Unsaturated Ester

Synthesis of Bridgehead Substituted Bicyclo[2.2.1]Heptanes. Radical Cyclization of an Oxime Ether and an α,β-Unsaturated Ester

1994 ◽  
Vol 47 (10) ◽  
pp. 1833 ◽  
Author(s):  
EW Della ◽  
AM Knill
Keyword(s):  
Radical Cyclization ◽  
Unsaturated Ester ◽  
Oxime Ether ◽  
Similar Treatment ◽  
Tributyltin Hydride

The synthesis of bicyclo[2.2.1]heptanes with useful functionality at each bridgehead is achieved by radical cyclization of appropriately substituted 4-methylene- and 4-benzyloxyimino- cyclohexylmethyl radicals. The latter process, for example, leads to a bridgehead amine. Optimum yields are achieved when the reactions are conducted at 110� with slow addition of tributyltin hydride; under these conditions, the uncyclized isomer is either not detected, or formed in very small quantity. Production of a mixture of five- and six-membered cycloalkanones from similar treatment of the analogous 4-oxocyclohexylmethyl radicals reveals that the reaction is medicated by the corresponding 1-norbornyloxy radical.

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