J. Meijer

Regio- and stereo-chemical features of the stannylcopper(I)-induced substitution in propargylic substrates

Abstract Stannylcopper(I) species, R 3 SnCu and [R 3 Sn] 2 CuLi, preferentially convert propargylic substrates, R 1 CCCR 2 R 3 X (X = Br, MeCO 2 , MeS(O)O or MeSO 3 ) into allenes R 3 Sn(R 1 )CCCR 2 R 3 . Only when the group R 1 causes much greater steric hindrance than with R 2 and R 3 is the acetylenic product R 1 CCCR 2 SnR 3 formed. The stereochemical course of the allene formation has been studied in both the steroid and non-steroid series, and found to be mainly or exclusively anti.

Palladium(0)-promoted cross-coupling of allenylmetal compounds with aryl and vinyl iodides. A novel route to aryl- and vinyl-substituted allenes

Abstract The reaction of allenylmetal compounds, RR{′}CCCHM (I), with aryl and vinyl iodides, R I, have been studied. With Pd(PPh3)4 as catalyst a highly regioselective formation of allenes, RR{′}CC CHR″ (II), has been observed for MgCl, Cu, Cu1/2,Li1/2, Ag, Ag1/2Li1/2, or ZnCl, but not Li. The reaction of the iodides proceeds with retention of configuration.

Allenylcopper(I) compounds: suitable reagents for the synthesis of allenynes☆

Abstract Allenylcopper(I) compounds react smoothly and highly regioselectively with 1-iodo-1-alkynes to give allenynes in excellent yields.

Organosilver(I) chemistry: On the reaction of RAg and R2AgMgCl compounds with conjugated enynenitriles

Abstract The addition of RAg and R 2 AgMgCl to enynenitriles is described. RAg reagents prefer to transfer their R group to the double bond of these nitriles, so that after protolysis 2,3-alkadienenitriles are obtained, while the homoargentates generally give 2,4-alkadienenitriles. The regio- and stereo-chemical course of the reactions are compared with those in additions of RCu and R 2 CuMgCl to the enynenitriles.