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Full-Text Articles in Physical Sciences and Mathematics

Ytterbium Triflate Catalyzed Synthesis Of Alkoxy-Substituted Donor-Acceptor Cyclobutanes And Their Formal [4 + 2] Cycloaddition With Imines: Stereoselective Synthesis Of Piperidines., Mahmoud M Abd Rabo Moustafa, Brian L Pagenkopf Oct 2010

Ytterbium Triflate Catalyzed Synthesis Of Alkoxy-Substituted Donor-Acceptor Cyclobutanes And Their Formal [4 + 2] Cycloaddition With Imines: Stereoselective Synthesis Of Piperidines., Mahmoud M Abd Rabo Moustafa, Brian L Pagenkopf

Chemistry Publications

A new synthesis of 2-alkoxy-1,1-cyclobutane diesters and their first use in dipolar cycloadditions is reported. Both the formation of the donor-acceptor cyclobutanes and their subsequent annulation with in situ formed imines are catalyzed by Yb(OTf)(3). Cyclobutanes with carbon donor groups give piperidines with high trans stereoselectivity.


Formal [4 + 2] Cycloaddition Of Alkoxy-Substituted Donor-Acceptor Cyclobutanes And Aldehydes Catalyzed By Yb(Otf)3., Mahmoud M Abd Rabo Moustafa, Andrew C Stevens, Ben P Machin, Brian L Pagenkopf Oct 2010

Formal [4 + 2] Cycloaddition Of Alkoxy-Substituted Donor-Acceptor Cyclobutanes And Aldehydes Catalyzed By Yb(Otf)3., Mahmoud M Abd Rabo Moustafa, Andrew C Stevens, Ben P Machin, Brian L Pagenkopf

Chemistry Publications

The cycloaddition between 2-alkoxy-1,1-cyclobutane diesters and aromatic, heteroaromatic, or aliphatic aldehydes under Yb(OTf)(3) catalysis generates tetrahydropyrans in high yields with exclusive cis-stereochemistry.


Diels-Alder Chemistry Of Siloles And Their Transformation Into Cyclohex-2-Ene-1,4-Cis-Diols., Andrew C Stevens, Brian L Pagenkopf Jul 2010

Diels-Alder Chemistry Of Siloles And Their Transformation Into Cyclohex-2-Ene-1,4-Cis-Diols., Andrew C Stevens, Brian L Pagenkopf

Chemistry Publications

The synthesis of siloles with substitution patterns that are continuative toward natural product synthesis are described. Their reactivity in Diels-Alder chemistry was explored through thermal, Lewis acid, and high-pressure reactions. Furthermore, bicyclic adducts were oxidatively cleaved to reveal a highly functionalized cyclohexene core.


Synthesis Of 5-Azaindoles Via A Cycloaddition Reaction Between Nitriles And Donor-Acceptor Cyclopropanes., Mahmoud M Abd Rabo Moustafa, Brian L Pagenkopf Jun 2010

Synthesis Of 5-Azaindoles Via A Cycloaddition Reaction Between Nitriles And Donor-Acceptor Cyclopropanes., Mahmoud M Abd Rabo Moustafa, Brian L Pagenkopf

Chemistry Publications

A new method for the synthesis of 5-azaindole derivatives is reported. A [3+2] dipolar cycloaddition between nitriles and a 3,4-cyclopropanopiperidine followed by SeO(2) oxidation affords the target compounds in moderate to excellent yields. The divergent nature and cost effectiveness of this method makes it very suitable for combinatorial applications in the pharmaceutical industry.