array of functional group transformations. The unprecedented spiro B-N heterocycles prepared in this study have potential utility as buildingblocks for the synthesis of pharmaceuticals. Preliminary mechanisticstudies suggest that insertion of the alkylidene carbenes into the B-H bonds of the amine-borane adducts proceeds via a concerted process involving a three-membered-ring transition state.
Organocatalytic 1,4‐Addition Reaction of 2‐Formyl(thio)esters to Vinylketones: An Efficient Access to Acyclic Chiral Building Blocks with a Quaternary Carbon Stereocenter
2‐Formyl(thio)esters were utilized as pronucleophiles to obtain less‐accessible acyclicchiralbuildingblocks bearing versatile functional groups on a quaternarycarbon atom for enantioselective 1,4‐addition to vinylketones. To achieve high enantioselectivity in the present 1,4‐additionreaction, thiourea‐tertiary amines containing a bulky chiral backbone were developed as catalysts, and several derivatizations
Method of preparing a 3-alkoxy-2-alkyl-propionic acid ester derivative
申请人:Bracco Industria Chimica S.p.A.
公开号:US04278808A1
公开(公告)日:1981-07-14
3-Alkoxy-2-alkyl-propionic acid derivatives are prepared by catalytic hydrogenation of the acrylic acid analogs. The latter are obtained by CO treatment of lower alkyl esters of alkanoic acids having 3-6 carbon atoms in the presence of alkali metal methylate and condensation of the resulting 2-formylalkanoic acids or their alkali metal enolates with compounds of the formula X--(CH.sub.2).sub.m --Z wherein X is Cl, Br, or OH, and Z is Cl, Br, I, alkyl- or arylsulfonyl, or OH.
Verfahren zur Herstellung von Omega-Formylalkancarbonsäureestern
申请人:BASF Aktiengesellschaft
公开号:EP0295554A1
公开(公告)日:1988-12-21
Ein Verfahren zur Herstellung von ω-Formylalkancarbonsäureestern durch Hydroformylieren von Alkencarbonsäureestern mit Kohlenmonoxid und Wasserstoff bei erhöhter Temperatur und unter erhöhtem Druck in Gegenwart von Kobaltcarbonylkomplexen, wobei man α,β-ungesättigte Alkencarbonsäureester in Gegenwart von 0,01 bis 1 Mol% Kobaltcarbonylkomplexen, berechnet als Kobalt unter Einhaltung eines Umsatzes an α,β-ungesättigten Alkencarbonsäureestern von 10 bis 70 % hydroformyliert.