Synthesis of γ-Acetoxy β-Keto Esters Through Regioselective Hydration of γ-Acetoxy-α,β-alkynoates
摘要:
The At(I)-catalyzed regioselective hydration of gamma-acetoxy-alpha,beta-acetylinic ester by the assistance of a neighboring carbonyl group has beets developed. Varieties of simple primary, secondary, and tertiary gamma-acetoxy-alpha,beta-acetylinic esters, even those bearing sensitive functional group in the remote reaction sites, are selectively hydrated to the corresponding beta-keto esters. The reaction' tolerates a wide variety of other carboxylates, such as benzoates, propionates, acrylates, and pivalates, including chiral carboxylates with retention of the configuration. The broad substrate scope, including the derivatization of complex natural products and neutral and open air conditions, makes this atom economical approach very practical. O-18 labeling experiments disclose that the oxygen transposition occurs from the carboxylate group to the triple bond, not from water.
Catalytic (3+2) Palladium‐Aminoallyl Cycloaddition with Conjugated Dienes
作者:Barry M. Trost、Zhongxing Huang
DOI:10.1002/anie.201900693
日期:2019.5.6
application of tailored aminoallyl precursors for catalytic (3+2) cycloaddition with conjugateddienes via a Pd‐aminoallyl intermediate. The new cycloaddition reactions override the conventional (4+3) selectivity of aminoallyl cation cycloaddition through a sequence of Pd‐allyl transfer and ring closure. A variety of highly substituted or fused pyrrolidine rings were synthesized using the cycloaddition, and can
Phosphine–copper(I) complexes efficiently catalyzed the mono-boration of electron-deficient alkynes in the presence of MeOH and also catalyzed conjugate reductions of alkenylboronates bearing an electron-withdrawing group. The mono-addition of bis(pinacolato)diboron to alkynes catalyzed by a copper–Xantphos complex produced vinylboronates with high regio and stereoselectivity and asymmetric reduction
Rhodium-Catalyzed Tandem Cyclization: Formation of 1<i>H</i>-Indenes and 1-Alkylideneindans from Arylboronate Esters in Aqueous Media
作者:Mark Lautens、Tzvetelina Marquardt
DOI:10.1021/jo049722p
日期:2004.7.1
functionalized organorhodium intermediate which can cyclize onto nonterminal acetylenes in good to excellent yields. The catalytic system involves the use of electron-rich, sterically bulky ligands as tri-tert-butylphosphonium tetrafluoroborate stabilizing the organorhodium intermediates and reduces the incidence of protodeboronation in aqueous media.
Supportedgoldnanoparticlescatalyze the semihydrogenation of alkynes to alkenes with ammonia borane or amine borane complexes in excellent yields and under mild conditions. Internal alkynes provide cis-alkenes, making this protocol an attractive alternative of the classical Lindlar's hydrogenation.
[EN] SUBSTITUTED PARA-BIPHENYLOXYMETHYL DIHYDRO OXAZOLOPYRIMIDINONES, PREPARATION AND USE THEREOF<br/>[FR] PARA-BIPHÉNYLOXYMÉTHYL-DIHYDRO-OXAZOLOPYRIMIDINONES SUBSTITUÉES, LEUR PRÉPARATION ET LEUR UTILISATION
申请人:SANOFI AVENTIS
公开号:WO2011034828A1
公开(公告)日:2011-03-24
The present invention relates to a series of substituted para-biphenyloxymethyl dihydro oxazolopyrimidinones of formula (I) as defined herein. This invention also relates to methods of making these compounds including novel intermediates. The compounds of this invention are modulators of metabotropic glutamate receptors (mGluR), particularly, mGluR2 receptor. Therefore, the compounds of this invention are useful as pharmaceutical agents, especially in the treatment and/or prevention of a variety of central nervous system disorders (CNS), including but not limited to acute and chronic neurodegenerative conditions, psychoses, cognition deficit disorders, convulsions, anxiety, depression, migraine, pain, sleep disorders and emesis.