522603-79-8Relevant academic research and scientific papers
Ring-opening reactions of oxabicyclic alkene compounds: Enantioselective hydride and ethyl additions catalyzed by group 4 metals
Millward, Dan B.,Sammis, Glenn,Waymouth, Robert M.
, p. 3902 - 3909 (2000)
Titanium and zirconium catalysts selectively catalyze either the ethyl or hydride addition to [2.2.1] 4,5-bis(methoxymethyl)-7-oxabicycloheptene (6); the ring-opened products formed depend on catalyst, temperature, alkylaluminum reagent, and the concentration of alkylaluminum. Bis(neoisomen-thylindenyl)zirconium dichloride catalyzes the ethyl addition ring-opening of 6 to produce (1R,-2S,3S,6R)-2,3-bis(methoxymethl)-6-ethylcyclohex-4-enol (7) in 96% ee. Zirconium catalysts catalyze the ring-opening of [3.2.1] 2,4-dimethyl-3-(benzyloxy)-8-oxabicyclo-6-octene (7) when ethylmagnesium bromide is used as a reagent. Both hydride and ethyl addition products are obtained at all conditions studied. Bis(neoisomenthylindenyl)zirconium dichloride catalyzes the ethyl addition ring-opening of 7 to produce ( 1S,2A,3S,4S,4S,7s)-2,4-dimethyl-3-(benzyloxy)-7-ethyl-5-cydohexen-1-ol (8) in 48% ee.
Copper-catalyzed ring-opening of heterobicyclic alkenes with Grignard reagents: Remarkably high anti-stereocontrol
Arrayas, Ramon Gomez,Cabrera, Silvia,Carretero, Juan Carlos
, p. 1205 - 1219 (2007/10/03)
Unlike most of the reported protocols for the ring-opening reaction of heterobicyclic alkenes with carbon nucleophiles which typically occur with syn selectivity, the alkylative ring-opening reaction of [2.2.1]oxa- and azabicyclic alkenes with Grignard reagents in the presence of a catalytic amount of copper(I) takes place with very high or complete anti-stereocontrol under smooth reaction conditions. This new procedure proved to be wide in scope with respect to both the Grignard reagent and the bicyclic alkene. Especially noteworthy is the facile ring-opening reaction of low reactive substrates such as nonaromatic oxabicyclic alkenes and azabenzonorbornadienes under this catalyst system. Georg Thieme Verlag Stuttgart.
Copper-catalyzed anti-stereocontrolled ring opening of oxabicyclic alkenes with Grignard reagents
Gomez Arrayas, Ramon,Cabrera, Silvia,Carretero, Juan C.
, p. 1333 - 1336 (2007/10/03)
(Matrix presented) A general copper-catalyzed procedure for the stereoselective ring opening of [2.2.1]-oxabicyclic alkenes with Grignard reagents is described. In the presence of catalytic amounts of CuCl/PPh 3 the reaction occurs with very high or complete anti selectivity in all cases.
