Regioselective epoxide opening for lysergic acid

Hiroaki Ohno and co-workers from Kyoto University have reported in JOC on their total synthesis of lysergic acid via a regioselective epoxide opening using a reducing agent.

JOC paper

Autocatalysis may be a rising field

Carreira and co-workers have reported in ACIEE on an autocatalysis reaction.  Normally we think of an asymmetric reaction involving the substrate, reagent, and a catalyst with a chiral ligand.  In this case, they are adding a fourth realm:  the product itself and in enantiomerically pure form.  They are saying that the addition of the product which is in high ee would increase the overall enantioselectivity of this reaction.  I have some questions about this like:  wouldn’t the composition of the enantiomerically pure product you’re adding to the reaction contribute to the ee of the final reaction?

ACIEE paper

Cyclobutenones from Allenoates

Shengming Ma and co-workers at Zhejiang University have reported in JACS on the usefulness of allenoates – you can make cyclobutenones.

 

JACS paper

A Cool Cascade

Chi-Sing Lee and co-workers at Peking University have published in Organic Letters on a cascade reaction that leads to 5,6-bicyclic rings.  This reaction catalyzed by zinc (II) bromide involves a Diels-Alder reaction followed by a reaction that looks like the Conia-ene reaction.

 

OL paper

Reformatsky-Claisen Cascade

Jeffrey Johnson and co-workers at UNC have published in JACS on a Refoormatzky-Claisen condensation cascade reaction where the second enolate generated opens a beta-lactone.

 

JACS paper

Zn/Yb-Mediated Conia-Ene Reaction

Jin-Heng Li and co-workers from Hunan Normal University have published in Synthesis on a Conia-ene reaction using Yb and Zn.  This reaction is catalytic in zinc but stoichiometric in ytterbium.  When a terminal alkyne is used, the cyclization is in the exo-dig mode, but when an internal alkyne is used, the cyclization is in the endo-dig mode.

Synthesis paper

Huperine Skeleton

Pierre-Yves Renard and co-workers at CNRS UMR have published in Tetrahedron on the synthesis of huperine skeleton via a Friedlander condensation using aluminum trichloride to generate a cyclohexanone from a mesylate in the presence of 2-amino-4-chlorobenzonitrile.

Tetrahedron paper

Enol Acetate Cross Coupling

Zhang-Jie Shi and co-workers from Peking University have recently reported in Chemistry a European Journal on a nickel catalyzed cross coupling between an enol acetate and an aryl boroxine.

Chemistry a European Journal paper

Ketoxime to Amide

Lal Dhar Yadav and co-workers at the University of Allahabad have recently reported in Synthesis on a rearrangement of a ketoxime (or hydroxyimine) to an amide using ZnCl2 and bromodimethylsulfonium bromide (BDMS).

Synthesis paper

Benzyne + Amide

Hideto Miyabe and co-workers at Hyogo University of Health Sciences have recently published in the carbonyl bond cleavage of amides using a benzyne substrate.

OL paper