Asymmetric addition of arylboroxines to cyclic N-sulfonyl ketimines proceeded in the presence of a rhodium catalyst coordinated with a chiral diene ligand to give high yields of benzosultams, where a triaryl-substituted stereogenic carbon center was created with high enantioselectivity (93-99% ee). The chiral benzosultams were transformed into the chiral (triaryl)methylamines by breaking the cyclic structure.

for single-crystal X-ray structure analysis, and Solvias AG for the generous gift of chiral ligands. J.Z. thanks SIOC for a postdoctoral fellowship. G.C.T. thanks NSERC for a postgraduate scholarship.Supporting information for this article is available on the WWW under http://dx.

An efficient trifluoromethylation reaction of alkynes using a fluoroform-derived CuCF3 reagent is described. The CF3 source is the inexpensive industrial waste fluoroform (CF3H). The air-stable CuCF3 reagent can be prepared in large quantities and is convenient to use. Synthetically useful trifluoromethylated alkynes containing a wide range of functional groups were successfully synthesized under mild conditions. Both terminal and TMS-protected alkynes gave the products in one step. The beneficial effect of a diamine ligand tetramethylethylenediamine (TMEDA) with the fluoroform-derived CuCF3 reagent was also demonstrated.

A stereoselective Pd(PPh3)4‐catalyzed C−F bond alkynylation of tetrasubstituted gem‐difluoroalkenes with terminal alkynes has been developed. This method gives access to a great variety of conjugated monofluoroenynes bearing a tetrasubstituted alkene moiety with well‐defined stereochemistry. Chelation‐assisted oxidative addition of Pd to the C−F bond is proposed to account for the high level of stereocontrol. An X‐ray crystal structure of a key monofluorovinyl PdII intermediate has been obtained for the first time as evidence for the proposed mechanism.

An efficient rhodium(I)-catalyzed addition of arylboronic acids to (benzyl-/arylsulfonyl)acetonitrile is described. Novel β-sulfonylvinylamine products are formed in a stereoselective fashion (Z-alkene). Upon hydrolysis, useful β-keto sulfones are obtained with a broad scope of aryl and sulfonyl substituents.