Diastereoselective Protonation, Substitution and Addition Reactions at Pseudotetrahedral Rhenium Complexes

Autor: Krzysztof Radacki, Wolfdieter A. Schenk, Frank Fischer, Frank Bock
Rok vydání: 2010
Předmět:
Zdroj: European Journal of Inorganic Chemistry. 2010:391-402
ISSN: 1099-0682
1434-1948
DOI: 10.1002/ejic.200901011
Popis: The chiral N,P ligand P(Me)(Ph)[8-(2-methylquinolinyl)] (3) was synthesized and separated into its enantiomers via diastereomeric palladium complexes. The reactions of 3 and (Rp)-3 with [CpRe(CO)(NO)(NCMe)]BF 4 (7) gave the diastereomeric complexes [CpRe(CO)(NO){P(Me)(Ph)-(C 10 H 8 N)}]BF 4 [8 and (R Re ,S P /S Re ,S P )-8], which, upon borohydride reduction, yielded the corresponding methyl complexes [CpRe(NO){P(Me)(Ph)(C 10 H 8 N)}(CH 3 )] [9 and (R Re ,S P / S Re ,S P )-9]. Treatment of 9 with HBF 4 under carefully controlled conditions gave the diastereomerically pure chelates [CpRe(NO){P(Me)(Ph)(C 10 H 8 N)}]BF 4 [(R Re ,S P /S Re ,R P )-10, (R Re ,R P /S Re ,S P )-10 and (R Re ,S P )-10]. The chelate ring was opened with NaSH to produce the hydrosulfido complexes [CpRe(NO){P(Me)(Ph)(C 10 H 8 N)}(SH)] [(R Re ,S P /S Re ,R P )-11, (R Re ,R P /S Re ,S P )-11 and (R Re ,S P )-11]. Each step in this sequence proceeded with retention of configuration at rhenium. Complex 11 underwent acid-promoted condensation with aldehydes to give thioaldehyde complexes [CpRe(NO){P(Me)(Ph)(C 10 H 8 N)}(S=CHR)]BF 4 (12a-d, R = Ph, Me, 4-C 6 H 4 OMe, C 6 F 5 ). The addition of nucleophiles X - to 12a gave rhenium-coordinated α-chiral thiolate complexes [CpRe(NO)(P(Me)(Ph)(C 10 H 8 N)}{SC(H)(Ph)(X)}] (13a-e, X = acac, PhCH 2 S, EtS, tBuS, CN) with 42-89 % de. The thiolate can readily be cleaved from the rhenium complex by a methylation/chelate ring-closure strategy. The stereochemistry of the entire reaction sequence was corroborated for each step by X-ray crystallography.
Databáze: OpenAIRE
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