- Electroreductive Carbofunctionalization of Alkenes with Alkyl Bromides via a Radical-Polar Crossover Mechanism
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Electrochemistry grants direct access to reactive intermediates (radicals and ions) in a controlled fashion toward selective organic transformations. This feature has been demonstrated in a variety of alkene functionalization reactions, most of which proceed via an anodic oxidation pathway. In this report, we further expand the scope of electrochemistry to the reductive functionalization of alkenes. In particular, the strategic choice of reagents and reaction conditions enabled a radical-polar crossover pathway wherein two distinct electrophiles can be added across an alkene in a highly chemo- and regioselective fashion. Specifically, we used this strategy in the intermolecular carboformylation, anti-Markovnikov hydroalkylation, and carbocarboxylation of alkenes - reactions with rare precedents in the literature - by means of the electroreductive generation of alkyl radical and carbanion intermediates. These reactions employ readily available starting materials (alkyl halides, alkenes, etc.) and simple, transition-metal-free conditions and display broad substrate scope and good tolerance of functional groups. A uniform protocol can be used to achieve all three transformations by simply altering the reaction medium. This development provides a new avenue for constructing Csp3-Csp3 bonds.
- Zhang, Wen,Lin, Song
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supporting information
p. 20661 - 20670
(2020/12/23)
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- Evaluation of several routes to advanced pregabalin intermediates: Synthesis and enantioselective enzymatic reduction using ene-reductases
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This publication describes the evaluation of four synthetic routes to the advanced pregabalin (Lyrica) intermediate 7. Asymmetric reduction of (E)-7 with an ene-reductase (OPR1 from Lycopersicon esculentum) gave a saturated cyanoester intermediate 5 with the desired S stereocenter in ≥99% ee. OPR1 also catalyzed the reduction of (Z)-7 to (S)-5, but with lower conversion and selectivity.
- Debarge, Sebastien,McDaid, Paul,O'Neill, Pat,Frahill, James,Wong, John W.,Carr, Donncha,Burrell, Adam,Davies, Simon,Karmilowicz, Mike,Steflik, Jeremy
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p. 109 - 121
(2014/05/20)
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- Rationalisation of the stereochemical outcome of ene-reductase-mediated bioreduction of α,β-difunctionalised alkenes
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The OYE1-3-mediated reductions of some α,β-difunctionalised alkenes, showing on the double bond a nitrile and ester group, are submitted to a careful stereochemical analysis, in order to identify which of the two electron-withdrawing groups (EWGs) is resp
- Brenna, Elisabetta,Crotti, Michele,Gatti, Francesco G.,Manfredi, Alessia,Monti, Daniela,Parmeggiani, Fabio,Pugliese, Andrea,Zampieri, Davila
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- PROCESS FOR THE PREPARATION OF ( S ) - 3 - CYANO - 5 - METHYLHEXANOIC ACID DERIVATIVES ADN OF PREGABALIN
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The invention provides a process for the manufacture of a compound of formula (I) using an enzyme catalysed reduction of a compound of formula (lla) or llb). Compounds of formula (I) are useful for preparing pregabalin.
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Page/Page column 23
(2012/03/26)
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