A short enantioselective synthesis of 3-epi-jaspine B and (+)-oxybiotin via an intramolecular tandem desilylation oxa-Michael addition strategy

RSC Advances ◽  
2014 ◽  
Vol 4 (91) ◽  
pp. 49770-49774 ◽  
Author(s):  
Anil M. Shelke ◽  
Varun Rawat ◽  
Arumugam Sudalai ◽  
Gurunath Suryavanshi
Keyword(s):  
Michael Addition ◽  
Addition Reaction ◽  
Enantioselective Synthesis ◽  
Asymmetric Epoxidation ◽  
Michael Addition Reaction ◽  
New Synthesis ◽  
Sharpless Asymmetric Epoxidation ◽  
Jaspine B

A new synthesis of cytotoxic 3-epi-jaspine B (34.7% overall yield; 97% ee) and (+)-oxybiotin (21.2% overall yield; 97% ee) is described starting from cis-2-butene-1,4-diol. The key reactions employed in the synthesis are Sharpless asymmetric epoxidation and a novel tandem desilylation-oxa Michael addition reaction.

Enantioselective Synthesis of β-Nitro Phosphonates Catalyzed by a Secondary Amine Bisthiourea

Synlett ◽  
2018 ◽  
Vol 29 (10) ◽  
pp. 1385-1389 ◽  
Author(s):  
Noor-ul Khan ◽  
Mohd Nazish ◽  
Ajay Jakhar ◽  
Naveen Gupta ◽  
Rukhsana Kureshy
Keyword(s):  
Spectroscopic Study ◽  
Secondary Amine ◽  
Michael Addition ◽  
Molecular Sieves ◽  
Addition Reaction ◽  
Probable Mechanism ◽  
Enantioselective Synthesis ◽  
Michael Addition Reaction

An enantioselective Michael addition of diphenyl phosphonate to nitroalkenes has been developed by using a secondary amine bisthiourea catalyst to access enantiomerically enriched β-nitro phosphonates. In this reaction, molecular sieves play a key role in achieving high and reproducible yields with a high enantioselectivities of up to 99% at –10 °C. A probable mechanism for the enantioselective Michael addition reaction was established by means of an NMR spectroscopic study.

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