The stereocontrolled synthesis of oligodeoxyribonucleoside phosphorothioates (PS-ODNs) using nucleoside 3'-O-oxazaphospholidine derivatives as monomer units is described. 2-Chloro-1,3,2-oxazaphospholidine derivatives were prepared from six kinds of enantiopure 1,2-amino alcohols and used for the phosphitylation reactions of 5'-O-protected nucleosides. A detailed study of these reactions reveale...

The diastereoselective double carbometalation reaction of cyclopropenes provides, in a single-pot operation, two ω-ene-[1,1]-bicyclopropyl ester derivatives. One regioisomer then undergoes Pd-catalyzed addition aryl iodide to provide skipped dienes possessing several distant stereocenters including congested quaternary carbon centers with excellent diastereoselectivity.

The regulation of ring-substituent diastereoselectivity in the intramolecular hydroamination/cyclisation (IHC) of alpha-substituted aminodienes by constrained geometry CGC-lanthanide catalysts (CGC=[Me(2)Si(eta(5)-Me(4)C(5))(tBuN)](2-)) has been elucidated by means of a reliable DFT method. The first survey of relevant elementary steps for the 1-methyl-(4E,6)-heptadienylamine substrate (1) and ...

The phosphine-catalyzed [4 + 2] annulations between allenoates and electron-poor trifluoromethyl ketones or N-tosylbenzaldimine dipolarophiles have been investigated in continuum solvation using density functional theory (DFT) calculations. The detailed reaction mechanisms as well as the high cis-diastereoselectivities of the reactions have been firstly clarified. Our calculated results reveal ...

An efficient and one-pot procedure is described for the synthesis of a variety derivatives 1,2-dihydrobenzo[f]chromen-3-ones 3,4-dihydrochromen-2-ones under solvent-free conditions via pseudo-four-component domino reaction acetic anhydride, aryl aldehydes, glycine-based dithiocarbamates, phenols/naphthols in presence l-proline H4[Si(W3O10)4].xH2O as green catalysts. All products were made strat...

A new tandem cross enyne metathesis (CEYM)-intramolecular Diels-Alder reaction (IMDAR) has been carried out. It involves conjugated ketones, esters or amides bearing a remote olefin and aromatic alkynes as the starting materials. The overall process enables the preparation of a small family of linear bicyclic scaffolds in a very simple manner with moderate to good levels of diastereoselectivity...

Heteroaromatic carboxylic acids have been directly coupled with imines using propylphosphonic anhydride (T3P) and NEt(iPr)2 to form azaspirocycles via intermediate N-acyliminium ions. Spirocyclic indolenines (3H-indoles), azaindolenines, 2H-pyrroles and 3H-pyrroles were all accessed using this metal-free approach. The reactions typically proceed with high diastereoselectivity and 3D shape analy...

Herbicide (±)-thaxtomin A has been synthesized in a one-pot process with a 32% isolated yield. A multicomponent coupling reaction was utilized to prepare in situ a dipeptide precursor which then sequentially underwent an alkaline mediated keto-amide cyclization to provide the target molecule. Adjustment of diastereoselectivity was achieved using microwave-induced irradiation. The approach incor...