Cationic Chiral Fluorinated Oxazaborolidines. More Potent, Second-Generation Catalysts for Highly Enantioselective Cycloaddition Reactions
作者:Karla Mahender Reddy、Eswar Bhimireddy、Barla Thirupathi、Simon Breitler、Shunming Yu、E. J. Corey
DOI:10.1021/jacs.6b00100
日期:2016.2.24
placement of fluorine substituents in the chiral ligand. This approach has led to a new, second-generation family of chiral oxazaborolidinium cationic species which can be used to effect many Diels-Alder reactions in >95% yield and >95% ee usingcatalyst loadings at the 1-2 mol % level. The easy recovery of the chiral ligand makes the application of these new catalysts especially attractive for large-scale
Studies on Lewis Acid-Mediated Intramolecular Cyclization Reactions of Allene-Ene Systems.
作者:Kunio HIROI、Takashi WATANABE、Akihiro TSUKUI
DOI:10.1248/cpb.48.405
日期:——
Lewis acid-mediated reactions of allene-ene compounds, derived from 3-methylcitronellal or dimethyl malonate, were carried out using various Lewis acids such as ethylaluminumdichloride, diethylaluminum chloride, titanium chloride, zinc chloride etherate, or boron trifluoride etherate, affording unexpectedly intramolecular [2+2]cycloaddition products under some particular reaction conditions without
Action des dialkylcuprates de lithium sur les aldéhydes α,β -éthylénioues
作者:C. Chuit、J.P. Foulon、J.F. Normant
DOI:10.1016/0040-4020(80)80126-8
日期:1980.1
Nearly exclusive 1-4 addition produts obtained by action of lithium dialkylcuprates with α,β ethylenic aldehydes. Non polar solvents and low temperatures favour this reaction .Only α,β-ehylenic aldehydes having a trisubstituted double bond give a relatively important proportation of 1–2 addition product.
THIOETHER DERIVATIVES AS PRECURSORS FOR A CONTROLLED RELEASE OF ACTIVE MOLECULES
申请人:FIRMENICH SA
公开号:US20160222327A1
公开(公告)日:2016-08-04
The present invention relates to the field of perfumery. More particularly, it concerns short chain β-sulfur carbonyl moieties capable of liberating an active molecule, such as a perfuming α,β-unsaturated ketone or aldehyde. The present invention concerns also the use of said compounds in perfumery as well as the perfuming compositions or perfumed articles comprising the invention's compounds.
calcination of the Sn–W hydroxide at 800 °C acts as an effective and reusable solid catalyst for CCbond‐formingreactions, such as the cyclization of citronellal, the Diels–Alder reaction, and the cyanosilylation of carbonyl compounds with trimethylsilyl cyanide (see scheme). The observed catalysis was truly heterogeneous, and the recovered catalyst could be reused without loss of its high catalytic performance