Reactions of Cp2TiMe2 with ferrocene and (ɳ5-Cp)Co(ɳ4-C4Ph4) derived esters and amides: A new route for 1-methylvinyl and methyl ketone derived metal sandwich compounds.

Reactions of Cp 2 TiMe 2 , with the ester derivatives of organometallic sandwich compounds (ɳ 5 -RC 5 H 4 )Fe(ɳ 5 -C 5 H 5 ) and (ɳ 5 -RC 5 H 4 )Co(ɳ 4 -C 4 Ph 4 ) (R=ester groups) gave products having R=C(CH 2 )Me, instead of the expected vinyl ethers indicating conversion of the ester units by Cp 2 TiMe 2 to methyl ketones followed by methylenation. A reaction of Cp 2 TiMe 2 with the diester (ɳ 5 -RC 5 H 4 )Co(ɳ 4 -C 4 Ph 3 R)(R C(O)OMe) also gave similar results. The study has also been successfully extended to metal sandwich derived amides, thio and seleno esters. By controlling the amount of Cp 2 TiMe 2 , the reactions were also stopped at the methyl ketone stage and the methyl ketones were isolated in good yields and characterized. The method provides an easy and direct access to convert organometallic sandwich derived esters and related compounds to 1-methylvinyl derived products. [ABSTRACT FROM AUTHOR]