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Archive for the ‘Alkaloids’ Category

Grandilodine C synthesis

Posted by naturalproductman on February 2, 2016

Atsushi Nishida and co-workers from Chiba University have reported in ACIE on the synthesis of grandilodine C.

 

ACIE paper

Posted in Alkaloids, Indoles, Total Synthesis | Leave a Comment »

Alkaloid dimer syntheses

Posted by naturalproductman on January 19, 2016

Mohammad Movassaghi and co-workers reported in JACS on the syntheses of (+)-asperazine (1), (+)-iso-pestalazine A (2), and (+)-pesta-lazine A (3).

 

JACS paper

Posted in Alkaloids, Dimer, Total Synthesis | Leave a Comment »

Gelsenicine synthesis

Posted by naturalproductman on January 18, 2016

Eric Ferreira and co-workers at the University of Georgia have reported in JACS on the synthesis of gelsenicine.

 

JACS paper

Posted in Alkaloids, Cascade Reactions, Methodology, Total Synthesis | Leave a Comment »

Isodaphlongamine H synthesis

Posted by naturalproductman on January 18, 2016

Stephen Hannessian and co-workers from Université de Montréal reported in ACIE on the synthesis of isodaphlongamine H.

 

ACIE paper

Posted in Alkaloids, Total Synthesis | Leave a Comment »

Simplifying retrosynthesis

Posted by naturalproductman on January 15, 2016

Richmond Sarpong and co-workers reported in Nature on the syntheses of weisaconitine D and liljestrandinine.

 

Nature paper

Posted in Alkaloids, Diterpenoids, Total Synthesis | Leave a Comment »

FtmOx1 forms the endoperoxide in verruculogen

Posted by naturalproductman on November 24, 2015

Here’s a great Nature paper from a three lab collaboration (Lixin Zhang lab at Carnegie Mellon University, Pinghua Liu lab at Boston University, and Yan Jessie Zhang lab at UT Austin) that characterized the enzyme that forms the endoperoxide-containing natural product, verruculogen. The enzyme is an alpha-ketoglutarate dependent iron containing enzyme.

 

What is interesting about this enzyme is that it forms a “Compound I” species (iron oxo complex), which in turn forms a tyrosine radical within the enzyme, and this tyrosine radical is what abstracts the C-H hydrogen in the starting material, fumitremorgin B. The resulting allylic radical comes together with a molecule of oxygen that in turn cyclizes to form an endoperoxide-containing radical intermediate. This radical intermediate abstracts the tyrosine hydrogen atom to reform a tyrosine radical and verruculogen.

The process of the iron-oxo intermediate abstracting a hydrogen atom from tyrosine reminds me of the way cyclooxygenase enzymes (COX1 and COX2 enzymes) work to form the endoperoxide, prostaglandin H2, from arachidonic acid. Furthermore, if you recall Michael Green’s work published in Science last year, there was a cytochrome P450 enzyme that also removes a hydrogen atom from a nearby tyrosine residue to form a tyrosine radical.

 

Nature paper

Posted in Alkaloids, Biosynthesis, Enzymes | Leave a Comment »

JOC papers of interest 11/24/2015

Posted by naturalproductman on November 24, 2015

James White and co-workers reported on the synthesis of Huperzine A.

Christopher Marvin and co-workers from Hendrix College reported in JOC on the synthesis of tetrabenazine through a photoredox reaction to afford the piperidone moiety.

Young-Ger Suh and co-workers from Seoul National University reported on the synthesis of galiellalactone.

Ronaldo Pilli and co-workers from  Universidad Estadualde Campinas have reported on the synthesis of cryptomoscatone E3.

Scott Denmark and colleague reported on an asymmetrice 2,3-Wittig rearrangement.

JOC 11.24.2015 FKY

Posted in Alkaloids, Light Mediated, Mechanistic, Methodology, Sigmatropic Rearrangements, Total Synthesis | Leave a Comment »

Massadine core synthesis

Posted by naturalproductman on October 28, 2015

Daesung Lee and co-workers reported in Organic Letters on the access of the cyclopentane ring core of massadine through a cyclohexane to cyclopentane ring contraction approach by oxidatively cleaving a 1,2-diol intermediate then cyclizing the resulting dialdehyde.
ring

Organic Letters paper

Posted in Alkaloids, Methodology, Ring contraction, Total Synthesis | Leave a Comment »

Epoxyeujindole synthesis

Posted by naturalproductman on October 28, 2015

Ang Li and co-workers from SIOC have reported in JACS on the synthesis of epoxyeujindole.

epoxyeujindole

JACS paper

JACS paper

Posted in Alkaloids, Indoles, Total Synthesis | Leave a Comment »

Spiroscytalin

Posted by naturalproductman on October 23, 2015

Nicholas Oberlies and co-workers from UNC Greensboro have reported in Tetrahedron on the isolation of spiroscytalin from a fungus.
spiroscytalin

Tetrahedron paper

Posted in Alkaloids, Tetramic acids | Leave a Comment »

 
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