3664-69-5Relevant academic research and scientific papers
An approach toward the total synthesis of subergorgic acid
Gilbert, John C.,Yin, Jiandong
, p. 5482 - 5490 (2008/12/20)
Ireland-Claisen rearrangement of a substituted alkenyl cyclopentanecarboxylate provided a monocyclic isomer containing the proper stereochemistry for four of the five stereogenic centers in subergorgic acid. Efforts to construct the additional rings in the molecule were thwarted as a result of steric and other factors. The results provide insights regarding the Ireland-Claisen rearrangement in five-membered ring systems. The formation of spiro-compounds from sterically and stereoelectronically demanding systems as reported herein has the potential to serve as a general strategy for the synthesis of such sub-units in both natural and unnatural products.
Cu-catalyzed asymmetric conjugate additions of alkylzinc reagents to acyclic aliphatic enones
Mizutani, Hirotake,Degrado, Sylvia J.,Hoveyda, Amir H.
, p. 779 - 781 (2007/10/03)
Cu-catalyzed enantioselective conjugate additions to acyclic aliphatic enones are reported. The resulting enolates may be functionalized intra- and intermolecularly, leading to the formation of an additional C-C bond. The utility of the present method is not limited to reactions involving Et2Zn; a variety of alkylzincs may be used. Moreover, many of the requisite substrates can be easily accessed through catalytic olefin cross metathesis. Copyright
Efficient Cu-catalyzed asymmetric conjugate additions of alkylzincs to trisubstituted cyclic enones
Degrado, Sylvia J.,Mizutani, Hirotake,Hoveyda, Amir H.
, p. 13362 - 13363 (2007/10/03)
The first examples of efficient catalytic asymmetric conjugate addition (ACA) of alkylzincs to trisubstituted cyclic enones is disclosed. These Cu-catalyzed reactions proceed efficiently with five- and seven-membered ring substrates to afford the desired products in ≥95% ee. Intermediate enolates can be trapped with alkyl halides to generate a quaternary stereogenic center. The requisite chiral ligand is prepared from commercially available materials and can be used in situ without further purification in the presence of commercial grade (CuOTf)2·PhMe. Copyright
Malonate Anion Induced Favorskii-Type Rearrangement. 3. Reaction of Methyl-Substituted α-Chlorocyclohexanones with Sodiomalonates
Sakai, Takashi,Tabata, Hideaki,Takeda, Akira
, p. 4618 - 4621 (2007/10/02)
The regioselectivity and the stereoselectivity of the ring-opening reaction of bicyclic cyclopropanols such as 6--3-methylbicyclohexan-6-ol (8) and 6--endo-2-methylbicyclohexan-6-ol (endo-9) and its exo-2-methyl isomer (exo-9) have been studied.Reaction of 2-chloro-4-methylcyclohexanone (2) with diethyl sodiomalonate (4b) gave 8 in 59percent yield.The similar reaction of 2-chloro-5-methylcyclohexanone (3) with 4b afforded a 44:56 mixture of endo-9 and exo-9 in 49percent yield.This mixture was separated to each component by means of HPLC.Reaction of 2-chloro-2-methylcyclohexanone (1) with 4b afforded only the substitution products.The alkaline hydrolysis (2 N NaOH) of 8 followed by pyrolysis gave trans-1-(3-methylcyclopentyl)ethanone (trans-11) selectively, while the acidic (6 N HCl) hydrolysis of 8 afforded a 1:1 mixture of cis- and trans-11 as a result of decarboxylation.The alkaline hydrolysis of endo-9 followed by pyrolysis gave a 50:34 mixture of cis- and trans-11 predominantly, whereas the acidid (35percent HCl) hydrolysis of endo-9 afforded trans-13 regio- and stereoselectively.The similar treatment of exo-9 never displayed such regioselectivity in the ring-opening reaction.
