Amide-Directed Catalytic Asymmetric Hydroboration of Trisubstituted Alkenes
作者:Sean M. Smith、James M. Takacs
DOI:10.1021/ja908257x
日期:2010.2.17
rhodium-catalyzed reaction is stereospecific. In addition, simple TADDOL-derived phenyl monophosphite ligands in combination with Rh(nbd)(2)BF(4) afford highly enantioselective catalysts (seven examples, 91-98% ee). These catalysts provide an alternative methodology to prepare Felkin or anti-Felkin acetate-aldol products and related derivatives that are obtainable from the intermediate chiral organoboranes
Tandem Regioselective Hydroformylation-Hydrogenation of Internal Alkynes Using a Supramolecular Catalyst
作者:Weiwei Fang、Bernhard Breit
DOI:10.1002/anie.201809073
日期:2018.11.5
electron‐withdrawing groups. By applying this novel catalytic system, a general protocol for the Rh‐catalysed hydroformylation‐hydrogenation of unsymmetrical internal alkynes, functionalized with a carboxylic acid, was found to furnish aliphatic aldehydes in high regio‐ and chemoselectivities. Control experiments confirm the enzyme‐like supramolecular catalyst mode of action.
A Mechanistic Dichotomy in Ruthenium-Catalyzed Propargyl Alcohol Reactivity: A Novel Hydrative Diyne Cyclization
作者:Barry M. Trost、Michael T. Rudd
DOI:10.1021/ja036410f
日期:2003.9.1
was tested in the reaction of diynes in the presence of water. Quite excitingly, cyclization comcommittant with addition of water to form 1-acylcycloalkenes occurs. This proves to be general process to form five- and six-membered rings. Interestingly, hydrative cyclization of Z-5-decen-2,8-diyne to 1-acetyl-2-ethyl-cyclohexa-1,4-diene occurs without isomerization of the doublebonds. Furthermore, the
Free radical cyclizations in alkaloid synthesis: (+)-heliotridine and (+)-hastanecine
作者:Joong-Kwon Choi、David J. Hart
DOI:10.1016/s0040-4020(01)97176-5
日期:1985.1
hydride and AIBN affords mixtures of reduction and cyclization products. Cyclization products partition between indolizidinones and pyrrolizidinones depending on the terminal alkyne substituent. When the terminal substituent is a trimethylsilyl group, synthetically useful yields of pyrrolizidinones are obtained. Applications of this chemistry to the synthesis of (+)-heliotridine (2) and (+)-hastanecine (3)
Development of an Alkyne Analogue of the de Mayo Reaction: Synthesis of Medium‐Sized Carbacycles and Cyclohepta[
<i>b</i>
]indoles
作者:David Tymann、Dina Christina Tymann、Ulf Bednarzick、Ljuba Iovkova‐Berends、Julia Rehbein、Martin Hiersemann
DOI:10.1002/anie.201808578
日期:2018.11.19
herein is a conceptionally novel photochemically triggered cascade process to these scaffolds. Key to the cascading ring‐expansion process is an unprecedented intramolecular alkyne analogue of the deMayoreaction.