13949-99-0Relevant academic research and scientific papers
Enantiodivergent syntheses of (-)- and (+)-dysibetaine CPa and N-desmethyl analog
Sakai, Michihiro,Tanaka, Kento,Takamizawa, Satoshi,Oikawa, Masato
, p. 4587 - 4594 (2014)
The first total syntheses of (-)-dysibetaine CPa and the antipode have been achieved using enantioselective solvolysis of meso-cyclic anhydride mediated by quinine derivative as an organocatalyst. The synthesis features a demonstration of an enantiodiverg
Total synthesis of (±)-dysibetaine CPa and analogs
Oikawa, Masato,Sasaki, Shota,Sakai, Michihiro,Ishikawa, Yuichi,Sakai, Ryuichi
, p. 5789 - 5802,14 (2020/09/15)
The syntheses of the marine sponge-derived γ-amino carboxylic acid dysibetaine CPa and five analogs in their racemic forms were successfully performed by taking advantage of an electron-withdrawing N-(4-nitrophenyl) group in the cyclopropanation reaction,
Simple large-scale preparation of 1,2,3-tris-acceptor substituted cyclopropanes
Kozhushkov, Sergei I.,Leonov, Andrei,De Meijere, Armin
, p. 956 - 958 (2007/10/03)
Triethyl (1α,2α,3β)cyclopropane-1,2,3-tricarboxylate (3aa), as well as diethyl (4ab) and dimethyl (1α,2β,3α)-1-acetylcyclopropane-2,3-dicarboxylate (4bb) have been prepared on a scale of up to 60 g by Michael initiated ring-closure (MIRC) cyclopropanation of dialkyl fumarates 1a,b with ethyl chloroacetate (2a) and chloroacetone (2b) in 62%, 51% and 56% yield, respectively. For the success of the new procedure it is essential to slowly add (within 5-7 h) the mixture of compounds 1 and 2 to a vigorously stirred suspension of K2CO3 in DMF in the presence of benzyltriethylammonium chloride.
Catalytic cyclopropanation of electron deficient alkenes mediated by chiral and achiral sulfides: Scope and limitations in reactions involving phenyldiazomethane and ethyl diazoacetate
Aggarwal, Varinder K.,Smitha, Helen W.,Hynd, George,Jones, Ray V.H.,Fieldhouse, Robin,Spey, Sharon E.
, p. 3267 - 3276 (2007/10/03)
Phenyldiazomethane reacts with electron deficient alkenes in the presence of catalytic amounts of transition metal catalyst [Rh2(OAc)4 was better than Cu(acac)2] and catalytic amounts of sulfide to give cyclopropanes. Pentamethylene sulfide was found to be superior to tetrahydrothiophene and the optimum solvent was toluene. Under these optimised conditions a range of enones were cyclopropanated in high yields. Cyclic enones and acrylates were not successful in this process. The use of the chiral 1,3-oxathiane derived from camphorsulfonyl chloride in 2 steps in this process furnished cyclopropanes in good yield and very high enantiomeric excess (>97% ee). The absolute stereochemistry of cyclopropane 10 was proven by X-ray analysis and the origin of the stereochemical induction has been rationalised. Extension of this work to include diazoesters was partially successful. Again pentamethylene sulfide was found to be superior to tetrahydrothiophene, but this time both Rh2(OAc)4 and Cu(acac)2 were found to be equally effective. Enones, fumarates and unsaturated nitro compounds worked well but simple acrylates and unsaturated aldehydes were not effective substrates. Control experiments were conducted in which the stabilised ylide was isolated and reacted with the less successful substrates and, whilst unsaturated aldehydes still gave low yields, simple acrylates gave high yields of the corresponding cyclopropane. The use of the chiral 1,3-oxathiane was not successful with these more stable diazo compounds.
