Detail of "140924-50-1"

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Nonracemic frontalin via copper- and palladium-based skeletal construction and the asymmetric dihydroxylation

Nonracemic frontalin via copper- and palladium-based skeletal construction and the asymmetric dihydroxylation. Santiago, Braulio; Soderquist, John A. (Dep. Chem., Univ. Puerto Rico, Rio Piedras 00931, P. R.). J. Org. Chem., 57(22), 5844-7 (English) 1992. 140924-50-1 is also in the experiment. CODEN: JOCEAH. ISSN: 0022-3263. DOCUMENT TYPE: Journal CA Section: 26 (Biomolecules and Their Synthetic Analogs) The new higher order organocuprate, Li2Cu(CN)[C(OMe):CH2]2, prepd. through a Sn ? Li ? Cu transmetalation sequence, was found to efficiently couple with allyl bromide producing 2-methoxy-1,4-pentadiene which is efficiently converted to the ketal I. Hydroboration of I with 9-BBNH and the selective oxidn. of this adduct with trimethylamine N-oxide produces 9-oxa-10-borabicyclo[3.3.2]decane (II), which undergoes Pd-catalyzed cross coupling with 2-bromopropene producing III, thereby accomplishing the construction of the frontalin carbon skeleton in 63% overall yield from allyl bromide. The Os-based dihydroxylation of III followed by ketalization either produces the racemic pheromone (±)-IV or, with the Sharpless catalytic asym. dihydroxylation (dihydroquinine ligand) procedure, results in the selective formation of the S enantiomer in 35% ee. The de detd. from the 13C NMR spectra of the diastereomeric Mosher's monoesters was found to provide useful corroborative information on the optical purity of the intermediate 1,2-diols. .

Organocatalytic asymmetric allylic carbon-carbon bond formation

Organocatalytic asymmetric allylic carbon-carbon bond formation. Poulsen, Thomas B.; Bell, Mark; Jorgensen, Karl Anker (Danish National Research Foundation: Center for Catalysis, Department of Chemistry, Aarhus University, Aarhus C DK-8000, Den.Chemical with cas number 140924-50-1 also plays role.). Organic & Biomolecular Chemistry, 4(1), 63-70 (English) 2006 Royal Society of Chemistry. CODEN: OBCRAK. ISSN: 1477-0520. DOCUMENT TYPE: Journal CA Section: 25 (Benzene, Its Derivatives, and Condensed Benzenoid Compounds) Organocatalytic allylic C-C bond-forming addn.Several substances like 140924-50-1 may be metioned in this study. of activated alkylidenes I [X = O, CH2, CH2CH2, R1 = H; X = CH2, R1 = 7-MeO, 6-MeO, 5,7-Me2, 6,7-(MeO)2] to alkyl and aryl nitroalkenes R2CH:CHNO2 (R2 = n-pentyl, cyclohexyl, Ph, 4-MeOC6H4, 2-naphthyl, 2-thienyl, etc.) has been achieved with high diastereo- and enantioselectivity. Chiral tertiary amine catalysts are used to give allyl intermediates which exhibit g-selectivity in the C-C bond forming step. The reactions proceed with up to > syn:anti ratio for both the alkyl- and aryl nitroalkenes with up 96% and 98% ee, resp. The products II of this conjugate addn. are transformed into a range of intermediates, such as optically active conjugated dienes and 1-substituted tetralones, which are difficult to access via alternative methods. ..