Ty. Lee et al., MANGANESE-MEDIATED SYNTHESIS OF CIS-DISUBSTITUTED CYCLOHEXADIENES VIADOUBLE NUCLEOPHILIC-ADDITION TO COORDINATED ARENES, Inorganica Chimica Acta, 214(1-2), 1993, pp. 125-134
The addition of carbon donor nucleophiles to (arene)Mn(CO)2L+ (L=CO, P
(OPh)3, PMe3), followed by replacement of a CO with NO+, affords monof
unctionalized (cyclohexadienyl)Mn(CO)(NO)L+ complexes (12). A study ha
s been made of nucleophilic addition to 12 to yield cyclohexadiene com
plexes (13). The yield of the reaction of 12 with soft stabilized carb
on donors (e.g. NaCH(CO2Et)CN) improves substantially when the ligand
L=CO is replaced by L=P(OPh)3 or PMe3. Hydride donors give good yields
of monofunctionalized cyclohexadiene complexes regardless of the natu
re of L. When L not-equal CO, significant chiral discrimination takes
place and the product is obtained as a mixture of diastereomers. Oxida
tion of the (cyclohexadiene)Mn(CO)(NO)L complexes with FeCl3 or Me3NO
generates the free hydrocarbon ligand as cis-disubstituted cyclohexa-1
,3-dienes or cyclohexen-1-ones, the latter resulting from hydrolysis o
f a methoxy substituent. Hard carbon donors such as LiPh and LiMe atta
ck a CO in 12, ultimately converting to trans-disubstituted cyclohexad
ienes. This work shows that the manganese-mediated double nucleophilic
addition to arenes can be an efficient route to functionalized cycloh
exadienes.