Enantioselektive Katalysen: LXXVIII. Der optisch aktive Phosphido-verbrückte Eisenkomplex [(η 5C 5H 5) 2Fe 2(μ-H)(μ-PMen 2)(CO) 2] — Synthese, Isome

Abstract

The hydrido-phosphido-bridged complex [(η 5-C 5H 5) 2Fe 2(μ-H)(μPMen 2)(CO) 2] ( 3) is prepared from [(η 5-C 5H 5)Fe(CO) 2] 2 ( 1) and dimenthylphosphine HPMen 2 in boiling toluene. The reaction proceeds via the intermediate [(η 5-C 5H 5) 2Fe 2(HPMen 2)(CO) 3] ( 2). 2 forms a pair of cis- trans isomers, whereas 3 consists of three isomers, the meso-isomer cis- 3 and the two diastereomers trans- 3a and trans- 3b. In hot toluene, 2 gives 1 and 3. In solution, 3 undergoes a photochemical cis- trans isomerization reaction. 3 is an enantioselective catalyst in the photochemical hydrosilylation of acetophenone with diphenylsilane to give 1-phenylethanol in up to 33% ee.