54807-91-9Relevant academic research and scientific papers
Studies on an Oxidative 1,4-Addition to s-trans-1,3-Dienes, a Key Reaction in a Strigol Total Synthesis
Galkina, Anna,Buff, Angelika,Schulz, Emmanuelle,Hennig, Lothar,Findeisen, Matthias,Reinhard, Gerd,Oehme, Ramona,Welzel, Peter
, p. 4640 - 4653 (2007/10/03)
Oxidation of 4,6-heptadienoic acid systems with hydrogen peroxide in the presence of a catalytic amount of diphenyl diselenide leads to 5-(3-hydroxypropenyl)dihydrofuran-2-one systems with defined relative configuration at the 4 and 7 positions (carboxylic acid numbering). A system having a six-membered ring as part of the s-trans-diene system was an intermediate in a strigol total synthesis; a second system lacking the six-membered ring is the subject of the present publication. We accomplished a stereoselective synthesis of the diene system by (i) trapping a π-allyl palladium complex with lithium diphenylphosphinite to give an allylic diphenylphosphane oxide and (ii) a subsequent Horner-Wittig reaction. The species that brings about the oxidative 1,4-addition is benzeneperoxyseleninic acid. We also report observations that shed some light on the mechanism. Wiley-VCH Verlag GmbH, 69451 Weinheim, Germany, 2002.
Straightforward regio- and stereo-selective synthesis of t-2-[(diphenylphosphinoyl)methyl]-c-3-(disubstitutedphosphinoyl)-r-1- cyclopentanols
Camps, Pelayo,Colet, Gisela,Font-Bardia, Mercè,Mu?oz-Torrero, Victoria,Solans, Xavier,Vázquez, Santiago
, p. 3473 - 3484 (2007/10/03)
A 3-step, regio- and stereo-selective, high-yielding synthesis of t-2-[(diphenylphosphinoyl)methyl]-c-3-(disubstitutedphosphinoyl)-r-1- cyclopentanols (8a-d) is described. Reaction of epoxides 2a-d and/or 5a-d with the lithium derivative of methyldiphenylphosphine oxide (9) gave cyclopentanols 8a-d. Base-catalyzed rearrangement of epoxides 2a-d and/or 5a-d led to 3-(disubstitutedphosphinoyl)cyclopent-2-en-1-ols (7a-d) which on reaction with the lithium derivative of 9 gave also 8a-d. The relative configurations of 2a and 8b-d were obtained by single crystal X-ray diffraction analysis.
Towards chiral non-racemic cis-1,3-disubstituted cyclopentane 1,4-diphosphines
Camps, Pelayo,Colet, Gisela,Font-Bardia, Merce,Muoz-Torrero, Victoria,Solans, Xavier,Vazquez, Santiago
, p. 759 - 778 (2007/10/03)
Reaction of dialkyl- or diaryl-trans-(3,4-epoxycyclopentyl)phosphine oxides 2 with the lithium derivative of methyldiphenylphosphine oxide gives a mixture of (±)-t-4- and (±)-c-4-(disubstituted phosphinoyl)-t-2-(diphenylphosphinoylmethyl)-r-1-cyclopentanol derivatives 13a-c and 16a-c, which could be obtained in pure form by separation of the corresponding acetates 14a-c and 17a-c followed by methanolysis. Compounds 13b and 16b were transformed into the corresponding dehydroxy derivatives 19 and 21 through the Barton procedure. Additionally, 16a was transformed into a diastereomeric mixture of carbamates 22 and 23 on reaction with (S)-α-phenylethylisocyanate which could be separated by repeated crystallization. The relative configuration of compounds 13b, 17a, 21 and 22 was established by X-ray diffraction analysis.
Aprotic Conjugate Addition of Allyllithium Reagents Bearing Polar Groups to Cyclic Enones. 2. 2-Alkyl-, 2,3-Dialkyl-, and 1,3-Dialkylallyl Systems
Haynes, Richard K.,Katsifis, Andrew G.,Vonwiller, Simone C.,Hambley, Trevor W.
, p. 5423 - 5433 (2007/10/02)
As an extension of the work carried out on the conjugate addition reactions of lithiated 3-alkylallylic sulfoxides, phosphine oxides, and phosphonates to cyclic enones, the effects of placing methyl groups at C2, at C2 and C3, and at C1 and C3 of the allyl system and of placing the allyl system within a five-membered ring are examined.From the lithiated 2-methallyl and (E)-2-methylbut-2-enyl ("tiglyl") sulfoxides, mixtures of diastereomeric (E)- and (Z)-vinilyc sulfoxides resulting from conjugate addition to cyclopentenone are obtained.The proportion of Z diastereomers formed increases with the reaction temperature.In contrast, lithiated (Z)-2-methylbut-2-enyl ("angelyl") sulfoxides and the tiglyl and angelyl phosphine oxides undergo highly diastereoselective conjugate addition to give (E)-vinylic products.Lithiated 1,3-dimethylbut-2-enyl sulfoxides undergo stereoconvergent reactions in that the starting sulfoxides, as mixtures of diastereomers, are converted into vinylic sulfoxides, which are obtained as single diastereomers.The individual diastereomers of tert-butyl cyclopentenyl sulfoxide upon lithiation undergo conjugate addition with cyclopentenone to give the same vinylic sulfoxide.A sulfenate ester also results from carbonyl addition.The structures of the diastereomers have been established by high-field (1)H NMR spectoscopy, by chemical correlation, and in two cases by X-ray crystallographic studies.The destabilizing influence of the methyl groups on the normal "trans-fused chair-chair"-like extended transition state causing access to "cis-fused boat-boat"-like, "cis-fused chair-chair"-like, and "trans-fused boat-chair"-like transition states involving planar lithiated reagents provides a rationale for the results.The temperature dependence of some of these reactions, and simple quenching experiments in which the individual lithiated diasteromers of the cyclopentenyl sulfoxide are converted into a single diasteromer, provide evidence for planar lithiated sulfoxides.
