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Full-Text Articles in Physical Sciences and Mathematics
Gram Scale Synthesis Of The C(18)-C(34) Fragment Of Amphidinolide C., Nicholas A Morra, Brian L Pagenkopf
Gram Scale Synthesis Of The C(18)-C(34) Fragment Of Amphidinolide C., Nicholas A Morra, Brian L Pagenkopf
Chemistry Publications
The synthesis of the C(18)-C(34) fragment of amphidinolide C has been achieved via two routes, culminating in both the shortest (11 steps) and highest yielding (26% overall yield) approaches to this segment. The highly convergent approach will facilitate the synthesis of analogues, including the C(18)-C(29) fragment of amphidinolide F. Synthetic highlights include the selective methylation of a diyne, and the highly efficient use of a second generation cobalt catalyst in the Mukaiyama oxidative cyclization to form the trans-THF ring.
Gram Scale Synthesis Of The C(18)-C(34) Fragment Of Amphidinolide C., Nicholas A Morra, Brian L Pagenkopf
Gram Scale Synthesis Of The C(18)-C(34) Fragment Of Amphidinolide C., Nicholas A Morra, Brian L Pagenkopf
Chemistry Publications
The synthesis of the C(18)-C(34) fragment of amphidinolide C has been achieved via two routes, culminating in both the shortest (11 steps) and highest yielding (26% overall yield) approaches to this segment. The highly convergent approach will facilitate the synthesis of analogues, including the C(18)-C(29) fragment of amphidinolide F. Synthetic highlights include the selective methylation of a diyne, and the highly efficient use of a second generation cobalt catalyst in the Mukaiyama oxidative cyclization to form the trans-THF ring.
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
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
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.
Increased Yields And Simplified Purification With A Second-Generation Cobalt Catalyst For The Oxidative Formation Of Trans-Thf Rings., Cory Palmer, Nicholas A Morra, Andrew C Stevens, Barbora Bajtos, Ben P Machin, Brian L Pagenkopf
Increased Yields And Simplified Purification With A Second-Generation Cobalt Catalyst For The Oxidative Formation Of Trans-Thf Rings., Cory Palmer, Nicholas A Morra, Andrew C Stevens, Barbora Bajtos, Ben P Machin, Brian L Pagenkopf
Chemistry Publications
The synthesis of a second-generation cobalt catalyst for the formation of trans-THF products via the Mukaiyama aerobic oxidative cyclization is reported. Two procedures have been developed with the new water-soluble catalyst that give superior yields and greatly simplify purification compared to the previous catalysts.
Synthesis Of Tetrahydroisoquinocarbazoles Via C-2 Alkylation Of Indoles With 2-Alkoxycyclopropanoate Esters., Barbora Bajtos, Brian L Pagenkopf
Synthesis Of Tetrahydroisoquinocarbazoles Via C-2 Alkylation Of Indoles With 2-Alkoxycyclopropanoate Esters., Barbora Bajtos, Brian L Pagenkopf
Chemistry Publications
A concise method for the synthesis of several tetrahydroisoquinocarbazole derivatives is reported, where the core is prepared in six steps from tryptophol in 51% overall yield. The pentacyclic analogs are constructed via a dipolar C-2 alkylation of a 3-substituted indole with a 2-alkoxycyclopropanoate ester and a SmBr(2)-HMPA mediated ketyl-alkene ring closure.
Total Synthesis Of (+/-)-Goniomitine Via A Formal Nitrile/Donor-Acceptor Cyclopropane [3 + 2] Cyclization., Christian L Morales, Brian L Pagenkopf
Total Synthesis Of (+/-)-Goniomitine Via A Formal Nitrile/Donor-Acceptor Cyclopropane [3 + 2] Cyclization., Christian L Morales, Brian L Pagenkopf
Chemistry Publications
The total synthesis of (+/-)-goniomitine has been accomplished in 17 linear steps with 5.2% overall yield starting from commercially available delta-valerolactam. A synthetic highlight includes the first application of a formal [3 + 2] cycloaddition between a highly functionalized nitrile and a donor-acceptor cyclopropane to prepare an indole nucleus. The use of a microwave reactor is shown to greatly improve the reaction times for two steps.
First Total Synthesis And Structural Reassignment Of (-)-Aplysiallene., Jian Wang, Brian L Pagenkopf
First Total Synthesis And Structural Reassignment Of (-)-Aplysiallene., Jian Wang, Brian L Pagenkopf
Chemistry Publications
The first total synthesis of (-)-aplysiallene has been completed in 16 steps and features a key sequential Mukaiyama aerobic oxidative cyclization to prepare the fused bis-THF core. The original stereochemical assignment has been revised as shown.
C-2/C-3 Annulation And C-2 Alkylation Of Indoles With 2-Alkoxycyclopropanoate Esters., Barbora Bajtos, Ming Yu, Hongda Zhao, Brian L Pagenkopf
C-2/C-3 Annulation And C-2 Alkylation Of Indoles With 2-Alkoxycyclopropanoate Esters., Barbora Bajtos, Ming Yu, Hongda Zhao, Brian L Pagenkopf
Chemistry Publications
The annulation reaction between various indoles and 2-alkoxycyclopropanoate esters is reported. Both high efficiency and complete stereochemical control were observed in some cases with this annulation process. A single stereocenter on the cyclopropane controls the diastereoselective formation of up to four new stereocenters. A different reaction course was observed with 3-substituted indole substrates, and an intervening C-3 to C-2-migration process arose that gives synthetically useful C-2 alkylation indole products.