Highly diastereoselective entry to chiral oxindole-based β-amino boronic acids and spiro derivatives

Author(s):  
Marco Manenti ◽  
Stefano Gazzotti ◽  
Leonardo Lo Presti ◽  
Giorgio Molteni ◽  
Alessandra Silvani

We here describe the first Cu-catalysed, diastereoselective 1,2-addition of 1,1-diborylmethane to chiral ketimines for the synthesis of quaternary stereocenters and spiro compounds. The method provides easy access to a range...

2007 ◽  
Vol 2007 (8) ◽  
pp. 468-471 ◽  
Author(s):  
Madhukar S. Chande ◽  
Rahul R. Khanwelkar ◽  
Pravin A. Barve

Novel routes for the synthesis of spiro derivatives anthrone have been designed using a Michael addition reaction followed by a Dieckmann condensation and Thorpe–Ziegler cyclisation. Bis-Michael addition of pyrazole-5-thione with 1,5-diarylpenta-1,4-dien-3-one gave directly a spiro derivative of pyrazole-5-thione. An enol lactone was synthesised by using mono Michael addition on dimedone, followed by hydrolysis and condensation.


2016 ◽  
Vol 18 (15) ◽  
pp. 4216-4227 ◽  
Author(s):  
Nongthombam Geetmani Singh ◽  
Makroni Lily ◽  
Shougaijam Premila Devi ◽  
Noimur Rahman ◽  
Aziz Ahmed ◽  
...  

Vitamin B1 functionalised nano-ferrites: an organo-nanocatalyst for the synthesis of various spiro derivatives.


2019 ◽  
Vol 9 (4) ◽  
pp. 262-267
Author(s):  
Mohamed Zaki ◽  
Abdelouahd Oukhrib ◽  
Mohammed Loubidi ◽  
Ahmed El Hakmaoui ◽  
Marie-Aude Hiebel ◽  
...  

Background: In recent decades, natural products are an important source of chemotherapeutics as more than half of the effective cancer drugs can be traced to natural origins. Objective: Moreover, the modification of natural products is one of the most common and fruitful approaches to obtain novel therapeutic agents in medicinal chemistry. Method: Continuing with a research project based on the support of Moroccan plant resources. we report herein the use of α-isocostic acid extracted in enantiomerically pure form from Dittrichia viscosa as a convenient starting material for the synthesis of new eudesmane derivatives. Results: Novel spiro derivatives with a natural scaffold were prepared. Spiro-isoxazolidine derivatives were generated on the exocyclic double bond adjacent to the ester α,β-unsaturated function by 1,3-dipolar cycloaddition of methyl α-isocostate 1 derived from sesquiterpenic isocostic acid, with nitrones 2. Conclusion: This procedure allowed us to generate enantiomerically pure spiro compounds in one diastereoisomer form with a limited number of steps. These compounds were fully characterized by spectroscopic methods.


Synlett ◽  
2019 ◽  
Vol 30 (17) ◽  
pp. 2004-2009 ◽  
Author(s):  
Vindya K. Gopinatha ◽  
Hassan A. Swarup ◽  
Sathees C. Raghavan ◽  
Kempegowda Mantelingu ◽  
Kanchugarakoppal S. Rangappa

A vital approach for the synthesis of a range of novel thioxotriaza-spiro derivatives is described. These new heterocyclic systems are obtained via oxalic acid catalyzed reaction of α,β-unsaturated ketones in the presence of 5,6-diamino-2-mercaptopyrimidine-4-ols; thus, spiro rings are constructed in one step. Notably, this transformation involves condensation of an amino group followed by enamine reaction with alkenes and subsequent reaction promoted by oxalic acid to afford spiro compounds with excellent regioselectivity.


RSC Advances ◽  
2016 ◽  
Vol 6 (106) ◽  
pp. 104556-104559 ◽  
Author(s):  
Gopinathan Muthusamy ◽  
Sunil V. Pansare

A flexible synthesis of allyl vinyl ethers, precursors of functionalized quaternary stereocenters, was developed by employing a regioselective Petasis olefination of haloallyl oxalates and subsequent cross-coupling with alkyl- and aryl boronic acids.


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