Influence of N-substituted lactams on acyclic free radical based hydrogen transfer
摘要:
anti Relative stereochemistry is achieved in the hydrogen-transfer reaction of a lactam adjacent to the carbon-centered radical. The sense of diastereoselectivity is reversed using N-substituted lactams, and optimal results favoring syn reduced products are obtained with an alpha -methylbenzyl group and a Boc group. (C) 2001 Elsevier Science Ltd. All rights reserved.
An efficient synthesis of the C1−C17 western unit of narasin was achieved from (S)-Roche ester. Highlights in our synthesis include the successful exploitation of three stereoselective sequences of Lewis acid mediated reaction followed by free-radical-based hydrogen transfer.
[EN] NUCLEOSIDE AND NUCLEOTIDE ANALOGUES BEARING A QUATERNARY ALL-CARBON STEREOGENIC CENTER AT THE 2' POSITION AND METHODS OF USE AS A CARDIOPROTECTIVE AGENT<br/>[FR] ANALOGUES DE NUCLÉOSIDES ET DE NUCLÉOTIDES PORTANT UN CENTRE STÉRÉOGÈNE TOUT CARBONE QUATERNAIRE EN POSITION 2' ET PROCÉDÉS D'UTILISATION EN TANT QU'AGENT CARDIOPROTECTEUR
申请人:LCB PHARMA INC
公开号:WO2018049534A1
公开(公告)日:2018-03-22
Nucleoside and nucleotide analogues that can be used as cardioprotective agents are provided. The nucleosides and nucleotide analogues comprise tetrahydrofuranyl or tetrahydrothienyl moieties with quaternary stereogenic all-carbon centers at the 2' position and a phosphonate ester at the 5' position.
Diastereoselective Hydrogen-Transfer Reactions: An Experimental and DFT Study
作者:François Godin、Michel Prévost、Serge I. Gorelsky、Philippe Mochirian、Maud Nguyen、Frédérick Viens、Yvan Guindon
DOI:10.1002/chem.201300377
日期:2013.7.8
an equatorial orientation. Hydride deliveries to different acyclic substrates and calculations also suggest that the higher anti‐selectivities obtained with borinate intermediates are not related to the formation of a complex mimicking an exocycle. From a broader standpoint, this study reveals important conformational factors for reactions taking place at a center vicinal to a heterocycle or an α‐alkoxy
Synthesis of Propionate Motifs: Diastereoselective Tandem Reactions Involving Anionic and Free Radical Based Processes
作者:Yvan Guindon、Karine Houde、Michel Prévost、Benoit Cardinal-David、Serge R. Landry、Benoit Daoust、Mohammed Bencheqroun、Brigitte Guérin
DOI:10.1021/ja010805m
日期:2001.9.1
employing a Mukaiyama reaction in tandem with a hydrogen transfer reaction for the elaboration of propionate motifs. The nature of the protecting groups on the chiral β-alkoxy aldehyde and the type of Lewis acid used are varied to modulate the stereochemical outcome of the tandemreactions. The mode of complexation is thus controlled (monodentate or chelate) for the Mukaiyama reaction to give access to
structure–activity study of a bioactive natural product containing polypropionate subunits requires that its stereoisomers also be evaluated. Therefore, a general approach to synthesize these motifs is necessary. We describe herein the synthesis of the C1–C13 polypropionate subunit of zincophorin and isomers thereof using a two-reaction sequence: an aldol reaction using a mixture of tetrasubstituted enoxysilanes