Stereoselective [3+2] Cycloaddition of Imino Esters with Nitroalkenes

Stereoselective synthesis of N-heterocycles through amine addition to nitroalkenes.

An efficient route for the preparation of substituted N-heterocycles was developed through the amine addition to nitroalkenes. The reaction tolerates a large substrate scope with good to excellent yields (up to 95%) and excellent stereoselectivities (up to 99 : 1 dr).

Stereoselective synthesis of activated 2-arylazetidines via imino-aldol reaction.

A simple and efficient synthetic route to substituted N-sulfinyl and N-sulfonyl azetidines is described involving imino-aldol reaction of ester enolates with racemic and non-racemic aldimines for obtaining β-amino esters as a key step. These β-amino esters on subsequent reduction followed by TsCl/KOH mediated cyclization produced the corresponding racemic and non-racemic azetidines with high yi...

Indium - mediated Allylation of α - Imino Esters in Aqueous Media

Phosphoramidite-Cu(OTf)2 complexes as chiral catalysts for 1,3-dipolar cycloaddition of iminoesters and nitroalkenes.

Chiral complexes formed by phosphoramidites such as (Sa,R,R)-9 and Cu(OTf)2 are excellent catalysts for the general 1,3-dipolar cycloaddition between azomethine ylides and nitroalkenes affording the corresponding tetrasubstituted proline esters mainly as exo-cycloadducts in high er at room temperature. The exo-cycloadducts can be obtained in enantiomerically pure form just after simple recrysta...

Stereoselective Formation of Trisubstituted Vinyl Boronate Esters by the Acid-Mediated Elimination of α-Hydroxyboronate Esters

The copper-catalyzed diboration of ketones followed by an acid-catalyzed elimination leads to the formation of 1,1-disubstituted and trisubstituted vinyl boronate esters with moderate to good yields and selectivity. Addition of tosic acid to the crude diboration products provides the corresponding vinyl boronate esters upon elimination. The trisubstituted vinyl boronate esters are formed as the...