937-44-0Relevant academic research and scientific papers
Conjugate Addition Reactions of Allylic Copper Species Derived from Grignard Reagents: Synthetic and Spectroscopic Aspects
Lipshutz, Bruce H.,Hackmann, Claus
, p. 7437 - 7444 (2007/10/02)
A general study on the 1,4-addition chemistry of allyl, methallyl, crotyl, and prenyl Grignard-derived organocopper reagents has been conducted.While diallylic cuprates formed from such species are not effective Michael donors, the 1:1:1 combination of an
Allylbarium reagents: Unprecedented regio- and stereoselective allylation reactions of carbonyl compounds
Yanagisawa, Akira,Habaue, Shigeki,Yasue, Katsutaka,Yamamoto, Hisashi
, p. 6130 - 6141 (2007/10/02)
The first direct preparation of allylbarium reagents by reaction of in situ generated reactive barium with various allylic chlorides and their new and unexpected selective allylation reactions with carbonyl compounds are disclosed. Highly reactive barium was readily prepared by the reduction of barium iodide with 2 equiv of lithium biphenylide in dry THF at room temperature. A variety of carbonyl compounds reacted with barium reagents generated from (E)- or (Z)-allylic chlorides in THF at -78 °C. All reactions resulted in high yields with remarkable α-selectivities not only with aldehydes but also with ketones. The double bond geometry of the starting allylic chloride was completely retained in each case. Stereochemically homogeneous (E)- and (Z)-β,γ-unsaturated carboxylic acids were easily prepared in good yields by highly α-selective carboxylation of allylic barium reagents with carbon dioxide. A selective Michael addition reaction with α,β-unsaturated cycloalkanone was also achieved using an allylbarium reagent. Treatment of 2-cyclopentenone (1 equiv) with allylbarium chloride (2 equiv) in THF at -78 °C for 20 min afforded 3-allylcyclopentanone in 94% yield with a 1,4/1,2 ratio of >99/1. Furthermore, the in situ generated barium enolate was efficiently trapped with various kinds of electrophiles (Me2C=CHCH2Br, nC5H11CHO, and CH3COCl).
Preparation of Higher Order Cyano and "Non-Ate" Allyl Copper Reagents from the Reaction of Allyl Chlorides with a Formal Copper Anion
Stack, Douglas E.,Klein, Walter R.,Rieke, Reuben D.
, p. 3063 - 3066 (2007/10/02)
The generation of higher order and "non-ate" allyl organocopper reagents have been achieved through the low temperature reaction of allyl chlorides with a formal copper anion.The copper anion is generated via the low temperature reduction of Cu(I) complexes by two equivalents of lithium naphthalenide and then oxidatively adds to allyl chlorides with minimal homocoupling.These allyl organocopper reagents undergo substitution reactions with alkyl chlorides and epoxides as well as 1,4-conjugate addition reactions in good to excellent yields.
A Facile Synthesis of Bicycloalkan-1-ols. Evidence for Organosamarium Intermediates in the Samarium(II) Iodide Promoted Intramolecular Barbier-Type Reaction
Molander, Gary A.,McKie, Jeffrey A.
, p. 4112 - 4120 (2007/10/02)
Samarium(II) iodide (SmI2) has been successfully employed as a reductive coupling agent for the intramolecular Barbier-type synthesis of bicycloalkan-1-ols.Thus, a variety of 3-(ω-iodoalkyl)cycloalkanones, upon treatment with SmI2 and a catalytic q
New methodology for conjugate additions of allylic ligands to α,β-unsaturated ketones: Synthetic and spectroscopic studies
Lipshutz, Bruce H.,Ellsworth, Edmund L.,Dimock, Stuart H.,Smith, Robin A.J.
, p. 4404 - 4410 (2007/10/02)
Michael additions of allylic ligands, including allyl, methallyl, crotyl, and prenyl systems, to a variety of α,β-unsaturated ketones can be effected in synthetically useful yields with allylcopper reagents in the presence of trimethylchlorosilane. Low-te
TRANSPOSITION OXY-COPE ASSISTEE PAR LE TRIFLUOROACETATE MERCURIQUE EN QUANTITE STOECHIOMETRIQUE ET EN QUANTITE CATALYTIQUE
Bluthe, Norbert,Malacria, Max,Gore, Jacques
, p. 3277 - 3284 (2007/10/02)
Tertiary 1,5-hexadien-3-ols are transformed at room temperature into δ-ethylenic ketones in 35-90percent yields under two sets of conditions: treatment with one molar equivalent of mercuric trifluoroacetate followed by demercuration of the intermediate α-mercuro ketone with sodium borohydride; and treatment with 0.2 molar equivalent of the same salt in the presence of one molar equivalent of lithium trifluoroacetate or trifluoromethansulfonate.The reactions are highly stereoselective, the E isomer of the ketone forming 80-95percent of the product.The highest selectivity was observed under the second conditions.
Process for the preparation of 8-ethylenic carbonyl compounds
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, (2008/06/13)
Process for the preparation of δ-ethylenic carbonyl compounds of the formula (I) by the oxy-Cope rearrangement of a diethylenic alcohol of the formula (II), in the presence of a mercuric salt: in formulae (I) and (II), R1, R2, R
LATENT ACETONYLATION OF α,β-ENONES WITH ALLYLTRIMETHYLSILANE OR 2-METHYL-2-PROPENYLTRIMETHYLSILANE: SYNTHESIS OF 1,5-DIKETONES AND ANNELATION TO FUSED CYCLOHEXENONES
Hosomi, Akira,Kobayashi, Hiroshi,Sakurai, Hideki
, p. 955 - 958 (2007/10/02)
Acetonylation of α,β-enones can be achieved by either with (2-methyl-2-propenyl)trimethylsilane or with allyltrimethylsilane followed by oxidative cleavage of the double bond or by the Wacker reaction, respectively.Annelation of the 1,5-diketones is also
