REACTIONS OF (CO)5MNSI(CH3)3 AND CO WITH ALDEHYDES AND CYCLIC ETHERS - SYNTHESES OF FUNCTIONALIZED PENTACARBONYLMANGANESE ACYLS AND HOMOLOGATED ORGANIC-COMPOUNDS
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Reactions of (CO)5MnSi(CH3)3 (1) and CO with aldehydes RCHO and cyclic ethers OCH2(CH2)nCH2 (n = 0-2) give manganese acyls (CO)5MnCOCH(R)OSi(CH3)3 and (CO)5MnCOCH2(CH2) CH2OSi(CH3)3 (n = 0, 6; n= 1, 9; n= 2, 10) in 26-72% and 54-87 % yields, respectively. Experiments conducted in the absence of CO show that these transformations proceed via labile alkyl intermediates (CO)5MnCH(R)-OSi(CH3)3 and (CO)5MnCH2(CH2)nCH2OSi(CH3)3. Reactions of propylene oxide and cyclohexene oxide with 1 and CO give the manganese acyls expected from SN2 ring opening. When the reaction of 1 with aldehydes is conducted in the presence of (CO)5MnH under careful conditions, homologated aldehydes (CH3)3SiOCHRCHO form in 55-78% yields. Reaction of 1 and (CO)5MnH with oxetane gives (CH3)3- SiOCH2CH2CH2CHO (13, 38%) and (CH3)3SiOCHCH2CH2CH2O (14, 59%). Reaction of 9 and 10 with [(CH3CH2)2N]3S+Si(CH3)3F2- yields 7-butyrolactone (84-95%) and -valerolactone (60-85%), respectively. The mechanisms of these transformations, and their utility in organic and organometallic synthesis, are discussed. 1984, American Chemical Society. All rights reserved.