The versatility of alpha-chloropropargyl phenyl sulfide affords high stereo- and regioselectivities in indium-promoted coupling reactions under mild conditions.

Coupling reactions between alpha-chloropropargyl phenyl sulfide (11) and a series of aldehydes under aqueous conditions are reported. Not only is good stereoselectivity observed between syn and anti isomeric products, but excellent regioselectivity is also witnessed. In reactions using indium metal as a promoter, the propargyl functionality (12) is retained, unlike the use of more traditional metals that result in formation of products containing a mixture of both propargyl (12) and allene (13) moieties.

Diastereoselection during 1,2-Addition of the Allylindium Reagent to alpha-Thia and alpha-Amino Aldehydes in Aqueous and Organic Solvents.

The stereochemistry of the indium-promoted reaction of allyl bromide with alpha-thia (PhS and MeS), disubstituted alpha-amino (Bn(2)N, Me(2)N, isoindolyl), and protected alpha-amino aldehydes (Ac and Boc) in water has been evaluated. The reactions involving the sulfur derivatives are minimally diastereoselective, indicating that the allylindium reagent is not thiophilic. Chelation is not observed and pi-facial discrimination is achieved via Felkin-Ahn transition states under the steric control of the substituents.

Comparative Diastereoselectivity Analysis of Crotylindium and 3-Bromoallylindium Additions to alpha-Oxy Aldehydes in Aqueous and Nonaqueous Solvent Systems.

The couplings of crotyl bromide (1) and 1,3-dibromopropene (2) to a triad of conformationally unrestricted alpha-oxy aldehydes in water, aqueous THF (1:1), and anhydrous THF are described. In no example involving 1 was the formation of anti,syn product detected. The proportion of syn isomers reached a maximum (syn/anti = 5.