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Handbook of Functionalized Organometallics Applications in S

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10.9 Miscellaneous Reactions<br />

Incorporation <strong>of</strong> CO 2 <strong>in</strong>to the product has been found <strong>in</strong> the nickel-catalyzed<br />

coupl<strong>in</strong>g reaction <strong>of</strong> a term<strong>in</strong>al alkyne with an organoz<strong>in</strong>c reagent [242,243].<br />

IZn<br />

+<br />

CO 2Et<br />

OBn<br />

CO2 (1 atm)<br />

Ni(COD) 2,DBU<br />

82%<br />

BnO<br />

CO 2H<br />

CO 2Et<br />

Similarly,reaction <strong>of</strong> dienes with CO 2 <strong>in</strong> the presence <strong>of</strong> Ni(COD) 2 affords<br />

p-allylnickel complex. Upon treatment with Me 2Zn,the correspond<strong>in</strong>g dicerbonxylic<br />

acid is isolated. On the other hand,when the nickel <strong>in</strong>termediate is<br />

allowed to react with HCl,only monocarboxylation product is obta<strong>in</strong>ed [244].<br />

Asymmetric <strong>in</strong>duction is observed when (S)-MeO-MOP ligand is used [245,246].<br />

Ph<br />

Ph<br />

+ CO 2<br />

X<br />

Ni(COD) 2<br />

DBU<br />

Ph<br />

CO2H +<br />

CO2H Ph<br />

77% (40:60)<br />

HCl<br />

Ni<br />

O<br />

Ni(acac) 2/PPh 3<br />

CO 2 (1 atm), Me 2Zn X<br />

X=NTs 94%<br />

X = C(CO 2Me) 2 91%<br />

Ph<br />

O<br />

+<br />

CO 2H<br />

Ni<br />

Me 2Zn<br />

68%<br />

CO2Me H<br />

H<br />

O<br />

CO 2H<br />

H<br />

CO2Me X<br />

1. Ni(acac) 2/(S)-MeOMOP<br />

CO2 (1 atm), R2Zn X<br />

R<br />

2. CH2N2 H<br />

X=NTs,R=Ph 81%(95%ee)<br />

X=C(CO2Me) 2,R=Me 100%(94%ee)<br />

Me<br />

Ph<br />

O<br />

OMe<br />

PPh2 (S)-MeO-MOP<br />

Reductive coupl<strong>in</strong>gs <strong>of</strong> <strong>in</strong>ternal alkynes with epoxides <strong>in</strong> the presence <strong>of</strong><br />

Ni(COD) 2/Et 3B/PBu 3 furnish efficient synthesis <strong>of</strong> homoallylic alcohols. The reaction<br />

can occur both <strong>in</strong>ter- or <strong>in</strong>tramolecularly [247].<br />

439

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