triethylamine in dichloromethane stirred soln. of Sn educt and (C2H5)3N treated dropwise with methanesulfonyl chloride at 0°C, kept at 0°C for 4 h; dild. with CH2Cl2, washed at 0°C with H2O, aq. HCl, satd. aq. NaHCO3, org. phase dried, evapd. (vac.), crystd. (hexanes/C6H6); elem. anal.;

in tetrahydrofuran under dry Ar at 0°C, stirred soln. of (C6H5)3SnLi treated dropwise with soln. of (C6H5)3SnCH2CH(CH2OSO2CH3)2, kept at 25°C for 18h, refluxed for 3 h; H2O added, evapd. (vac.), partitioned between H2O and CH2Cl2, org. phase dried, evapd. (vac.), chromd. (SiO2, hexanes/CHCl3), crystd. (hexanes/EtOAc); elem. anal.;