1257080-99-1Relevant articles and documents
Sc(OTf)3-catalyzed intramolecular diastereoselective cyclization from tert-butoxycarbonyl to acyliminium ion
Mao, Zhuo-Ya,Wang, Chen,Nie, Xiao-Di,Han, Xiao-Li,Dong, Han-Qing,Si, Chang-Mei,Wei, Bang-Guo
, (2021)
An effective approach to access dyadic 1,3-oxazinan-2-ones 8a-8c and 4,4a,5,6-tetrahydro-[1,3]oxazino[3,4-a]quinolin-1(3H)-ones 8d-8h was developed through Sc(OTf)3-catalyzed intramolecular cyclization from tert-butoxycarbonyl to acyliminium io
Chemoselective Electrosynthesis Using Rapid Alternating Polarity
Baran, Phil S.,Carlson, Ethan,Edwards, Jacob T.,Hayashi, Kyohei,Kawamata, Yu,Saito, Masato,Shaji, Shobin,Simmons, Bryan J.,Waldmann, Dirk,Zapf, Christoph W.
supporting information, p. 16580 - 16588 (2021/10/20)
Challenges in the selective manipulation of functional groups (chemoselectivity) in organic synthesis have historically been overcome either by using reagents/catalysts that tunably interact with a substrate or through modification to shield undesired sites of reactivity (protecting groups). Although electrochemistry offers precise redox control to achieve unique chemoselectivity, this approach often becomes challenging in the presence of multiple redox-active functionalities. Historically, electrosynthesis has been performed almost solely by using direct current (DC). In contrast, applying alternating current (AC) has been known to change reaction outcomes considerably on an analytical scale but has rarely been strategically exploited for use in complex preparative organic synthesis. Here we show how a square waveform employed to deliver electric current - rapid alternating polarity (rAP) - enables control over reaction outcomes in the chemoselective reduction of carbonyl compounds, one of the most widely used reaction manifolds. The reactivity observed cannot be recapitulated using DC electrolysis or chemical reagents. The synthetic value brought by this new method for controlling chemoselectivity is vividly demonstrated in the context of classical reactivity problems such as chiral auxiliary removal and cutting-edge medicinal chemistry topics such as the synthesis of PROTACs.
Electrochemical Scaled-up Synthesis of Cyclic Enecarbamates as Starting Materials for Medicinal Chemistry Relevant Building Bocks
Tereshchenko, Oleksandr D.,Perebiynis, Maryana Y.,Knysh, Irina V.,Vasylets, Olesia V.,Sorochenko, Anna A.,Slobodyanyuk, Eugeniy Y.,Rusanov, Eduard B.,Borysov, Oleksandr V.,Kolotilov, Sergey V.,Ryabukhin, Sergey V.,Volochnyuk, Dmitriy M.
supporting information, p. 3229 - 3242 (2020/07/06)
The electrochemical Shono oxidation of Boc-protected cyclic amines was revised. The conditions for scalable electrochemical synthesis of cyclic enecarbamates were found. The developed protocol included recycling of the full range of used reagents, favoring to E-factor reduction according to Green Chemistry requirements. The method opened the way for the convenient preparation of previously uncommon materials, which could become useful synthetic intermediates. Their synthetic potential was evaluated in [2+1] and [2+2] cycloadditions as well as electrophilic functionalization. Moreover, functionalized enecarbamates with carbonyl groups in β-position were used as latent 1,3-bielectrophiles in classical heterocyclizations. In a case of the hydrazine, the corresponding unusually decorated pyrazoles were prepared. The proposed methodology is a straightforward tool for the design and synthesis of Medicinal Chemistry relevant building blocks. As examples, 5-fluoro pipecolic and 3-fluoro isonipecotic acids were synthesized starting from Boc-protected esters of the pipecolic and the isonipecotic acids respectively; the 5-step approach to pyrazole containing α-aminoacids with different linkers between the aminoacidic and pyrazole moieties was elaborated based on the cheapest commercially available racemic and chiral cyclic α-aminoacids; the convenient approach to the functionalized tetrahydropyrido[3,4-d]pyridazines was proposed starting from Boc-protected ester of the isonipecotic acids. (Figure presented.).
Expedient preparation of nazlinine and a small library of indole alkaloids using flow electrochemistry as an enabling technology
Kabeshov, Mikhail A.,Musio, Biagia,Murray, Philip R.D.,Browne, Duncan L.,Ley, Steven V.
supporting information, p. 4618 - 4621 (2015/01/08)
An expedient synthesis of the indole alkaloid nazlinine is reported. Judicious choice of flow electrochemistry as an enabling technology has permitted the rapid generation of a small library of unnatural relatives of this biologically active molecule. Furthermore, by conducting the key electrochemical Shono oxidation in a flow cell, the loading of electrolyte can be significantly reduced to 20 mol % while maintaining a stable, broadly applicable process.
