TRANSFORMATION OF MANGANESE ACYLS (CO)(5)MNC(O)CH2R (R = H, CH3, OCH3) INTO THEIR SILOXYVINYL DERIVATIVES (CO)(5)MNC(OSIET3)=CHR WITH TRIETHYLSILANE - AN APPROACH TO DOUBLE CARBONYLATION OF MANGANESE ALKYL COMPLEXES (CO)(5)MNCH2R

Treatment of the manganese acyl complexes (O0)(5)MnC(O)CH2R. [R = H (1 a), CH3 (1b), OCH3 (1c)] with triethylsilane gave stable alpha-triethy lsiloxyvinyl compounds (Z)-(CO)(5)MnC(OSiEt3)=CHR (3a-c). Carbonylatio n of 3a and 3b, followed by protonolysis of the resulting (CO)(5)MnC(O )C(OSiEt3)=CHR [R = H (5a), CH3 (5b)] provided their alpha-ketoacyl de rivatives (CO)(5)MnC(O)C(O)CH2R (6a and 6b), which represents a. net d ouble carbonylation of their alkyl precursors (CO)(5)MnCH2R.