39167-09-4Relevant academic research and scientific papers
NUCLEOPHILIC ELIMINATIVE RING FISSION OF BRIDGEHEAD SUBSTITUTED 1,3-BISHOMOCUBYL ACETATES
Klunder, A. J. H.,Valk, W. C. G. M. de,Verlaak, J. M. J.,Schellekens, J. W. M.,Noordik, J. H.,et al.
, p. 963 - 973 (1985)
The base induced cage fission of three different types of functionalized bridgehead substituted 1,3-bishomocubyl acetates, viz A, B and C is described.The synthesis of two 6-functionalized 1,3-bishomocubyl 4-acetates (type A), viz 4-acetoxypentacyclo2,5.03,9.04,8>decan-6-one 5 and its ethylene acetal 6 has been accomplished starting from the readily available Diels-Alder adduct 4.The synthesis of three 1,3-bishomocubyl 8-acetates (type B), viz 8-acetoxypentacyclo2,5.03,9.04,8>decan-6-one 15, its ethylene acetal 16 and the parent acetate 20has been carried out starting from the cyclopentadiene-benzoquinone adduct 7.Base induced homoketonization of 6, 16 and 20 leads regio- and stereospecifically to the thermodynamically favored half cage ketones 22, 28 and 31, respectively.In constrast, the cage opening of the β-ketoacetates 5 and 15 is essentially directed by the β-ketone function.In the case of 5, regiospecific cleavage of the central C4-C5 bond is observed producing in a stereospecific manner diketone 25 in quantitative yield.Under similar conditions, acetate 15 gives a complex mixture of cage opened products arising from further fragmentation of the initially formed diketone 34.Deuterium labeling experiments reveal an anti-Bredt behavior of half cage ketones 28 and 31.The synthesis of a bridgehead acetate of type C has been accomplished by stereoselective reduction of ketone acetate 5 with LiAlH(t-OBu)3 followed by mesylation.A mixture of epimers 36a and 36b (ratio 1:4) is obtained from which the predominant anti-epimer 36b could be isolated.An X-ray analysis established its structure.Base induced cage fission of 36b leads regiospecifically totetracyclo2,5.04,8>decenone 37.In constrast the syn-epimer 36a, under similar conditions, only affords the bridgehead alcohol 38.
A lipase catalyzed condensation reaction with a tricyclic diketone: yet another example of biocatalytic promiscuity
Majumder, Abir B.,Ramesh, Namakkal G.,Gupta, Munishwar N.
, p. 5190 - 5193 (2009)
Novozym 435 (a commercially available immobilized form of Candida antarctica lipase B) was found to catalyze a condensation reaction of 5-hydroxy-endo-tricyclo[5.2.1.02,6]deca-4,8-dien-3-one with acetaldehyde (enzymatically produced from vinyl acetate in situ) under low water conditions, in presence of 10% organic co-solvent (N,N-dimethyl formamide or pyridine), to form a bis-adduct. Even though the condensation reaction occurred with pyridine (acting as a base catalyst) in the presence of acetaldehyde and in the absence of enzyme, the reaction was very slow as compared to the enzymatic process. Thus, while the non-enzymatic process took 4 days to achieve 100% conversion; in presence of enzyme it was possible within 4 h.
Palladium-mediated phosphine-dependent chemoselective bisallylic alkylation leading to spirocarbocycles
Clavier, Hervé,Giordano, Laurent,Tenaglia, Alphonse
supporting information; experimental part, p. 8648 - 8651 (2012/09/22)
Cycles everywhere: The selectivity in the transformations of 1,3-diones to carbocycles by palladium-catalyzed bisallylic alkylations is strongly dependent on the phosphine that is employed (see scheme). Moreover, synthesized vinylcyclopentenes can be easily transformed into cycloheptadiene derivatives through a carboncarbon allylic bond cleavage.
Asymmetric desymmetrization of pseudo-meso 5-hydroxy-endo-tricyclo[5.2.1.02,6]deca-4,8-dien-3-ones
Ramesh, Namakkal G,Bakkeren, Frank J.A.D,Groot, Debby De,Passamonti, Umberto,Klunder, Antonius J.H,Zwanenburg, Binne
, p. 9877 - 9887 (2007/10/03)
A novel route to the enantiopure endo-tricyclodecadienone system has been accomplished starting from readily accessible pseudo-meso-5-hydroxy-endo-tricyclo[5.2.1.02,6]deca-4,8-dien-3- one. Desymmetrization using (S)-prolinol or its methyl ether leads to the corresponding enaminones in high yields and with a de of 50%. Complete separation of the diastereomers has been conveniently achieved via their acetates. The absolute stereochemistry of the major diastereomer was determined by single-crystal X-ray diffraction analysis. Reductive elimination of the chiral auxiliary with lithium aluminum hydride affords optically pure parent tricyclodecadienone in good overall yield.
Asymmetric desymmetrization of a pseudo-meso endo-tricyclo[5.2.1.02,6]deca-4,8-dien-3-one by chiral amines
Bakkeren, Frank J. A. D.,Ramesh, Namakkal G.,De Groot, Debby,Klunder, Antonius J. H.,Zwanenburg, Binne
, p. 8003 - 8006 (2007/10/03)
A novel route to the enantiopure endo-tricyclodecadienone system has been realized starting from the readily accessible pseudo-meso-5-hydroxy-endo-tricyclo[5.2.1.02,6]deca-4,8-dien-3-one 4. Dynamic kinetic resolution of (±)-4 using (S)-prolinol or its methyl ether leads to the corresponding enaminones 6b,c in high yields and with a de of 50%. Complete separation of the diastereomers of 6b is conveniently accomplished via their acetates. The absolute stereochemistry of the major diastereomer was shown to be ent-6b. Reductive elimination of the chiral auxiliary in ent-6b with lithium aluminum hydride affords optically pure parent tricyclodecadienone (+)-1 (X=H) in good overall yield.
