Total Synthesis of Palau’amine

Someone was bound to do it, but wow – Phil Baran and co-workers have synthesized palau’amine recently and reported their route in ACIEE.

ACIEE paper

Decarboxylative Coupling

Masahiko Miura and co-workers at Osaka University have recently published in Organic Letters on a C-C bond forming process that involves the decarboxylation of cinnamic acid to form a new bond with vinyl bromides.  The palladium (II) acetate catalyst required the use of stoichiometric LiOAc and LiCl additives.

OL paper

Pumiliotoxin via Intramolecular Diels-Alder

Stephen Fearnley and co-worker at CUNY at York College have recently published in JOC on the synthesis of pumiliotoxin via an intramolecular Diels-Alder reaction by refluxing the substrate containing an oxazolone dienophile in dichloro-ethylaluminum in 1,2-dichlorobenzene.  The cyclic oxazolone can become opened with methyl lithium to afford a methylamide.

JOC paper

Hetero-Diels-Alder: A Multi-Component Approach

Robert Batey and co-workers at the University of Toronto have recently published in JOC on the synthesis of tetrahydroquinolines from a hetero-Diels Alder using BF3 etherate as the Lewis Acid.

JOC paper

Hydroformylation followed by Reduction/Cyclization

Andre Mann and co-workers at CNRS have recently published in Organic Letters on a clever approach to form nitrogen containing rings from azide-containing bis-alkenes – the protocol calls for a hydroformylation followed by reduction of the azide and simultaneous cyclization/reduction to form alkaloids, lupinine and epiquinamide.

OL paper

9-deoxygelsemide

Giovanni Vidari and co-workers at the Universitat di Pavia in Italy have recently published in Organic Letters on the synthesis of 9-deoxygelsemide, a compound foud from a plant Gelsemium elegans Benth. found in Japan. This compound had an EC50 of 22.6 micromolar against A549 lung tumor cells.

OL paper

Celogentin C Synthesis

Based on his progress towards Lyconadin, we know that Steven Castle at BYU likes his radical chemistry.  His group has recently published in JACS on the synthesis of a cyclic peptide, celgentin C.  This compound has even stronger activity at tubulin polymerization (IC50 = 0.8 micromolar) compared to the already known compound, vinblastine (IC50 = 3.0 micromolar).  Interestingly, Gong Chen and co-workers at Pennsylvania State University have recently published in ACIEE on their synthesis of the same compound.

JACS paper

Chen’s ACIEE paper

Aldehyde Insertion

Ruben Martin and co-workers from the Institute of Chemical Research of Catalonia in Spain have recently published in JACS on the synthesis of cyclic ketones from bromo-aryl-aldehydes.  There is a loss of HBr and as a result, they have successfully obtained benzocyclobutenones, which look highly strained just by looking at them – three adjacent sp2 centers in a four membered ring.

JACS paper

Allyl-Aryl Coupling

Masaya Sawamura and co-workers at Hokkaido University have recently published in JACS on an aryl-allyl coupling where he used an aryl boronic acid to displace an allylic acetate via an Sn2 prime fashion. The metal used was palladium (II) acetate that made the cationic palladium species in-situ with silver hexafluoroantimonate, and this reaction is also stereospecific, retaining the ee from the starting allylic acetate.

JACS paper

Triphenylphosphine as a catalyst

Xiaofeng Tong and co-workers at the East China University have recently published in Chemistry – A European Journal on the coupling of tosyl imines and alkynes to produce conjugated double bonds.

Chemistry a European Journal paper