Designing new catalytic C-C and C-N bond formations promoted by organoactinides

TY - JOUR

T1 - Designing new catalytic C-C and C-N bond formations promoted by organoactinides

AU - Eisen, Moris S.

AU - Straub, Thomas

AU - Haskel, Ariel

N1 - Funding Information: This research was supported by The Israel Science Foundation administered by The Israel Academy of Sciences and Humanities under Contract No. 76/94-1 and by The Fund for the Promotion of Research at the Technion. T.S. thanks the Max-Planck-Gesellschaft, Germany, for a MINERVA postdoctoral fellowship.

PY - 1998/6/12

Y1 - 1998/6/12

N2 - Organoactinides of the type Cp*2AnMe2 (Cp*=C5Me5; An=Th; U) are active catalytic precursors for the oligomerization of terminal alkynes HC≡CR (R=alkyl, aryl, SiMe3). The regioselectivity and the extent of oligomerization depend strongly on the alkyne substituent R, whereas the catalytic reactivity is similar for both organoactinides. Reaction with tert-butylacetylene yields regioselectively the E-2,4-disubstituted 1-buten-3-yne dimer whereas trimethylsilylacetylene is regioselective trimerized to the E,E-1,4,6-tris(trimethylsilyl)-1,3-hexadiene-5-yne, with small amounts (3-5%) of the corresponding E-2,4-disubstituted 1-buten-3-yne dimer. Oligomerization with less bulky alkyl and aryl substituted alkynes produces a mixture of higher oligomers with no regioselectivity. Using the Cp*2ThMe2 catalyst, we have recently developed a strategic method to control the extent and in some cases the regioselectivity of the catalyzed oligomerization of nonbulky terminal alkynes to dimers and/or trimers. The metallocene catalytic precursors ensure the selective synthesis of small oligomers by the addition of specific amines. Catalytic "tailoring" to dimer and trimers can be achieved by using small or bulky amines, respectively. Kinetic and mechanistic data for the controlling experiments argue that the turnover-limiting step involves the acetylide actinide complex formation with the rapid insertion of the alkyne and protonolysis by the amine. The analog Cp*2UMe2 in the presence of primary amines induce the selective C-N bond formation, producing enamines which are tautomerized to the corresponding imines.

AB - Organoactinides of the type Cp*2AnMe2 (Cp*=C5Me5; An=Th; U) are active catalytic precursors for the oligomerization of terminal alkynes HC≡CR (R=alkyl, aryl, SiMe3). The regioselectivity and the extent of oligomerization depend strongly on the alkyne substituent R, whereas the catalytic reactivity is similar for both organoactinides. Reaction with tert-butylacetylene yields regioselectively the E-2,4-disubstituted 1-buten-3-yne dimer whereas trimethylsilylacetylene is regioselective trimerized to the E,E-1,4,6-tris(trimethylsilyl)-1,3-hexadiene-5-yne, with small amounts (3-5%) of the corresponding E-2,4-disubstituted 1-buten-3-yne dimer. Oligomerization with less bulky alkyl and aryl substituted alkynes produces a mixture of higher oligomers with no regioselectivity. Using the Cp*2ThMe2 catalyst, we have recently developed a strategic method to control the extent and in some cases the regioselectivity of the catalyzed oligomerization of nonbulky terminal alkynes to dimers and/or trimers. The metallocene catalytic precursors ensure the selective synthesis of small oligomers by the addition of specific amines. Catalytic "tailoring" to dimer and trimers can be achieved by using small or bulky amines, respectively. Kinetic and mechanistic data for the controlling experiments argue that the turnover-limiting step involves the acetylide actinide complex formation with the rapid insertion of the alkyne and protonolysis by the amine. The analog Cp*2UMe2 in the presence of primary amines induce the selective C-N bond formation, producing enamines which are tautomerized to the corresponding imines.

KW - C-C bond formation

KW - C-N bond formation

KW - Catalysis

KW - Hydroamination

KW - Oligomerization

KW - Organoactinides

UR - http://www.scopus.com/inward/record.url?scp=0032094191&partnerID=8YFLogxK

U2 - 10.1016/S0925-8388(98)00037-1

DO - 10.1016/S0925-8388(98)00037-1

M3 - 文章

AN - SCOPUS:0032094191

SN - 0925-8388

VL - 271-273

SP - 116

EP - 122

JO - Journal of Alloys and Compounds

JF - Journal of Alloys and Compounds

ER -