- Isothiocyanate Strategy for the Synthesis of Quaternary α-Amino Acids Bearing a Spirocyclic Ring System
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This study demonstrates that isothiocyanates derived from α-substituted α-amino acids are useful building blocks in the heteroannulation reactions with electron-deficient olefins. The developed strategy proceeds in a cascade manner and involves Michael addition followed by a cyclization via nucleophilic addition. Target, spirocyclic heterocycles bearing either a quaternary α-amino acid moiety or α-aminophosphonate group have been efficiently synthesized in very high yield (up to 99%) and with excellent stereocontrol. The usefulness of heterocycles obtained has been demonstrated in selected transformations. (Figure presented.).
- Frankowski, Sebastian,Gajda, Tadeusz,Albrecht, ?ukasz
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- Catalytic asymmetric 1,2-addition of α-isothiocyanato phosphonates: Synthesis of chiral β-hydroxy- or β-amino-substituted α-amino phosphonic acid derivatives
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α-Amino phosphonic acid derivatives are considered to be the most important structural analogues of α-amino acids and have a very wide range of applications. However, approaches for the catalytic asymmetric synthesis of such useful compounds are very limited. In this work, simple, efficient, and versatile organocatalytic asymmetric 1,2-addition reactions of α-isothiocyanato phosphonate were developed. Through these processes, derivatives of β-hydroxy-α-amino phosphonic acid and α,β-diamino phosphonic acid, as well as highly functionalized phosphonate-substituted spirooxindole, can be efficiently constructed (up to 99 % yield, d.r. >20:1, and >99 % ee). This novel method provides a new route for the enantioselective functionalization of α-phosphonic acid derivatives. Correct chirality critical: Organocatalytic asymmetric Adol-type and Mannich-type reactions of α-isothiocyanato phosphonate have been realized. Michael addition was also applicable under the same catalytic conditions. This versatile approach provides a new route for the synthesis of diverse highly optically active functionalized α-amino phosphonic acid derivatives. Copyright
- Cao, Yi-Ming,Shen, Fang-Fang,Zhang, Fu-Ting,Zhang, Jin-Long,Wang, Rui
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p. 1862 - 1866
(2014/03/21)
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- Convenient syntheses of novel 1-isothiocyano-alkylphosphonate diphenyl ester derivatives with potential biological activity
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Herein, we describe a convenient method for the syntheses of novel 1-isothiocyano-alkylphosphonate diaryl ester derivatives and their antiproliferative activity. The syntheses are based on dithiocarbamates obtained in situ with the use of carbon disulfide
- Psurski, Mateusz,Pigula, Marta,Winiarski, Lukasz,Oleksyszyn, Jozef,Ciekot, Jaroslaw,Wietrzyk, Joanna
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p. 5845 - 5847,3
(2020/08/20)
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