STEREOSPECIFIC SYNTHESES OF FUNCTIONALIZED IRON ALKYL COMPLEXES WITH A STEREOGENIC METAL CENTER FROM AN IRON FORMYL PRECURSOR

Treatment of the stable formyl complex Fe(C(5)Ph(5))(CO)(PMe(3))CHO (1 ) with an excess of methyl triflate and subsequent addition of NH4PF6 produces the secondary carbene complex [Fe(eta(5)-C(5)Ph(5))(CO)(PMe(3 ))(=CHOMe)][PF6] (2, 93%). Methyl lithium acts as a dealkylating reage nt with 2 to regenerate 1 (81%). Treatment of methoxycarbene complex 2 with LiAlH4 gives the methoxymethyl complex Fe(eta(5)-C(5)Ph(5))(CO)( PMe(3))(CH(2)OMe) (3) in 95% yield. Similarly, reaction of 2 with LIAl D(4) gives a 90: 10 mixture of Fe(eta(5)-C(5)Ph(5))(Co)(PMe(3))(CHDOMe ) (3 d(1), 80%) diastereoisomers. The carbene complex 2 reacts with Me ONa to give the iron dimethylacetal complex Fe(eta(5)-C(5)Ph(5))(CO)(P Me(3)){CH(OMe)(2)} (4, 55%). The cyano(methoxy)methyl complex Fe(eta(5 )-C(5)Ph(5))(Co)(PMe(3)){CH(CN)(OMe)} (5, 85%) is obtained from the re action of 2 with 1 equivalent of KCN. NMR analyses of the crude produc t revealed that complex 5 was formed as a 85:15 mixture of diastereois omers. The carbene complex 2 reacts with TMSC=CLi to afford a 90:10 mi xture of diastereoisomers of the stable methoxy(trimethylsilylethynyl) methyl iron complexes Fe(C(5)Ph(5))(CO)(PMe(3)) {CH(OMe)(C=CTMS)} (6). After extraction and filtration 6 is isolated as a pure diastereoisom er in 63% yield.