A new method for facile access to enantioenriched tertiary thioethers/alcohols.

Phosphine-catalyzed regiodivergent enantioselective C-2- and C-4-selective γ-additions of oxazolones to 2,3-butadienoates have been developed. The C-4-selective γ-addition of oxazolones occurred in a highly enantioselective manner when 2-aryl-4-alkyloxazol-5-(4H)-ones were employed as pronucleophiles. With the employment of 2-alkyl-4-aryloxazol-5-(4H)-ones as the donor, C-2-selective γ-addition of oxazolones took place in a highly enantioselective manner. The C-4-selective adducts provided rapid access to optically enriched α,α-disubstituted α-amino acid derivatives, and the C-2-selective products led to facile synthesis of chiral N,O-acetals and γ-lactols. Theoretical studies via DFT calculations suggested that the origin of the observed regioselectivity was due to the distortion energy that resulted from the interaction between the nucleophilic oxazolide and the electrophilic phosphonium intermediate.

The first phosphine-catalyzed enantioselective γ-addition of 3-fluoro-oxindoles to 2,3-butadienoates has been developed. A range of 3-fluoro-substituted oxindole substrates were employed, and oxindoles containing a 3-fluoro quaternary center were constructed in high yields and with excellent enantioselectivities. The γ-addition products could be converted readily to optically enriched 3-fluoro-3-allyl oxindole derivatives.

Regiodivergent enantioselective C‐2‐ and C‐4‐selective γ‐additions of oxazolones to 2,3‐butadienoates catalyzed by chiral phosphines are developed.

For the first time, amino-acid derived bifunctional phosphines are used as catalysts to synthesize a wide range of substituted thiazolone and oxazolone derivatives. Products are obtained in high yields and excellent enantioselectivities. The reported new method provides facile access to enantio-enriched tertiary thioethers [cf. (VII)]. -(WANG, T.; YU, Z.; HOON, D. L.; HUANG, K.-W.; LAN*, Y.; LU, Y.; Chem. Sci. 6 (2015) 8, 4912-4922, http://dx.

The addition product can be easily converted into the 3‐allyl substituted oxindole derivative (V).