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

Moris S. Eisen*, Thomas Straub, Ariel Haskel

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

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.

Original languageEnglish
Pages (from-to)116-122
Number of pages7
JournalJournal of Alloys and Compounds
Volume271-273
DOIs
StatePublished - 12 Jun 1998
Externally publishedYes

Keywords

  • C-C bond formation
  • C-N bond formation
  • Catalysis
  • Hydroamination
  • Oligomerization
  • Organoactinides

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