CH-Pi Interactions

I’ve heard of cation-pi interactions, which were popularized by people like Dennis Dougherty, but recently in JACS there’s a new theme: CH-Pi interactions. Karla Ramirez-Gualito and co-workers from the Universidad Autonoma Nacional de Mexico have recently published in JACS on this idea using nOes to identify which regions of a sugar molecule contaning acetyl and oxygen heteroatoms interact with the solvent of benzene.

JACS paper

Palau’amide Synthesis

Kiyotake Suenaga and co-workers from Keio University have recently published in Tetrahedron Letters on the synthesis of palau’amide, a cytotoxic depsipeptide that has an IC50 towards KB cells at 13 nM.

Tetrahedron Letters paper

Mycolactones toxic to Fish

Kishi and co-workers at Harvard have recently reported in Chem Comm on the structure of a mycolactone from Mycobacterium marinum, which infects freshwater fish.

Chem Comm paper

Asymmetric Heter-Diels-Alder Reaction

Shunichi Hashimoto and co-workers from Hokkaido University have recently published in Chem Comm on an classic reaction – the Diels-Alder using Rawal’s diene and an aldehyde as the dienophile.  The reaction is also enantioselective.  They used a chiral rhodium dimer catalyst:  Rh2(S-BPTPI)4 (dirhodium(II) tetrakis[N-benzene-fused-phthaloyl-(S)-piperidinonate]).

Chem Comm paper

Aldol that Didn’t Disturb the Diazo Group

Xiaoming Feng and co-workers from Sichuan University have recently published in Chemical Communications on a Sc-catalyzed asymmetric Aldol reaction using a pyrrolidine-N-oxide or piperidine-N-oxide ligand.  Probably what stands out the most from the paper is that they used a alpha-diazoester as the nuclephile – something I would have expected to be reactive in the transformation.

 

Chem Comm paper

An Exciting Approach to Synthesize 5,5-Bicycles

Gregory Fu and co-workers at MIT have recently published in ACIEE on the synthesis of diquinanes starting from an ynone-enoate substrate using a tri-n-butyl-phosphine catalyst. Looks like he based the reaction from Tomita’s work which was published in Organic Letters back in 2003 where Tomita had the same catalyst but instead used an alkyne-dione system.

 

ACIEE paper

Tomita’s OL paper

**There’s a typo in the paper mis-spelling Tomita’s name in the first sentence.

Radical Cascade

David Procter and co-workers at the University of Manchester have recently published in Tetrahedron on a radical cascade cyclization that involves a dialdehyde enoate substrate that forms four contiguous centers.

 

Tetrahedron paper

Transannular [4+3]

Benjamin Gung and co-workers at the University of Miami in Ohio have recently published in the European Journal of Organic Chemistry on the synthesis of 6,7,6-tricyclic ring structures from a macrocycle using a gold catalyst.

 

European Journal of Organic Chemistry paper

Dihydropyran Cascade

Cheng Ma and co-workers at Zhejiang University have recently reported in ACIEE on a cascade reaction that involves the use of a beta-bromo-alpha,beta-unsaturated enal and a beta,gamma-unsaturated alpha keto ester to form a spirocyclic center and an acetal.

ACIEE paper

Synthesis of Vinyl Fluorines

Fluorine containing organic compounds are always interesting in terms of their biological activity.  Jinbo Hu and co-workers at the Shanghai Institute of Organic Chemistry have recently published in ACIEE where they used a nitrone and a sulfoximine to stereoselectively form the Z-olefin.  It’s similar to a Julia olefination but it’s more selective (100:0, Z:E selectivity was reported).

ACIEE paper