A Study on the Asymmetric Synthesis of β-Lactams through Double Stereodifferentiating Cycloaddition Reactions

1996 ◽  
Vol 61 (26) ◽  
pp. 9186-9195 ◽  
Author(s):  
Claudio Palomo ◽  
Jesús M. Aizpurua ◽  
Antonia Mielgo ◽  
Anthony Linden
Keyword(s):  
Asymmetric Synthesis ◽  
Cycloaddition Reactions

Asymmetric Synthesis of Cyclic β-Amino Acids via Cycloaddition Reactions

ChemInform ◽  
2006 ◽  
Vol 37 (27) ◽  
Author(s):  
Jose Barluenga ◽  
Bernardo Olano ◽  
Josefa Florez ◽  
Carlos Valdes
Keyword(s):  
Amino Acids ◽  
Asymmetric Synthesis ◽  
Cycloaddition Reactions

Asymmetric Synthesis of Isoxazole and Trifluoromethyl‐Containing 3,2’‐Pyrrolidinyl Dispirooxindoles via Squaramide‐Catalysed [3 + 2] Cycloaddition Reactions

2022 ◽  
Author(s):  
Tong-Hao Li ◽  
Da-Ming Du
Keyword(s):  
Asymmetric Synthesis ◽  
Cycloaddition Reactions ◽  
New Class ◽  
Highly Efficient

A highly efficient squaramide‐catalysed asymmetric domino Michael/Mannich [3 + 2] cycloaddition of 3‐methyl‐4‐nitro‐5‐ isatylidenyl‐isoxazoles and N‐2,2,2‐trifluoroethylisatin ketimines was developed. A new class of complex and skeletondiversified isoxazole and trifluoromethyl‐containing 3,2’‐pyrrolidinyl...

Asymmetric Synthesis of Cyclic β-Amino Acids via Cycloaddition Reactions

2005 ◽  
pp. 215-240 ◽  
Author(s):  
José Barluenga ◽  
Bernardo Olano ◽  
Josefa Flórez ◽  
Carlos Valdés
Keyword(s):  
Amino Acids ◽  
Asymmetric Synthesis ◽  
Cycloaddition Reactions

Asymmetric synthesis of podophyllotoxin analogs

1990 ◽  
Vol 68 (11) ◽  
pp. 2022-2027 ◽  
Author(s):  
James L. Charlton ◽  
Guy L. Plourde ◽  
K. Koh ◽  
Anthony S. Secco
Keyword(s):  
Asymmetric Synthesis ◽  
Natural Product ◽  
Good Yield ◽  
Diels Alder ◽  
Cycloaddition Reactions ◽  
Thermal Generation ◽  
Methyl Lactate ◽  
Model Studies ◽  
Diastereomeric Excess ◽  
Absolute Stereochemistry

Two analogs of podophyllotoxin, with the same absolute stereochemistry as the natural product, have been synthesized from the cycloadduct between α-hydroxy-α′-phenyl-o-quinodimefhane and the fumarate of S-methyl lactate. After initial attempts to produce the cycloadduct from photochemically generated α-hydroxy-α′-phenyl-o-quinodimethane failed, a study of the thermal generation and reaction of α-hydroxy-o-quinodimethane with the fumarate and acrylate of S-methyl lactate was made. A comparison was made of the diastereoselectivity of these cycloaddition reactions to those previously reported, in which the o-quinodimethane was generated photochemically. The α-hydroxy-o-quinodimethane was produced both by the known thermolysis of benzocyclobutenol and by thermolysis of 1-hydroxy-1,3-dihydrobenzo[c]thiophene-2,2-dioxide. The diastereomeric excess for the cycloaddition reactions was found to be greater than 95% with modest (ca. 55%) isolated yields of the major cycloadducts. Following these model studies, it was found that α-hydroxy-α′-phenyl-o-quinodimethane produced thermally from 1-hydroxy-3-phenyl-1,3-dihydrobenzo[c]thiophene-2,2-dioxide could be added to the fumarate of S-methyl lactate with high diastereoselectivity and good yield. The product of this reaction was converted to the podophyllotoxin analogs 7 and 17. Keywords: o-quinodimethanes, asymmetric, Diels–Alder, lactate, podophyllotoxin, lignan.

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