Thermodynamics, Kinetics, and Mechanism of (silox)3M(olefin) to (silox)3M(alkylidene) Rearrangements (silox = tBu3SiO; M = Nb, Ta)

Description:

Article discussing the thermodynamic, kinetic, and mechanism of (silox)3M(olefin) to (silox)3M(alkylidene) rearrangements (silox = tBu3SiO; M = Nb, Ta).

Creator(s):
Creation Date: March 10, 2005
Partner(s):
UNT College of Arts and Sciences
Collection(s):
UNT Scholarly Works
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Hirsekorn, Kurt F.

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Publisher Info:
Publisher Name: American Chemical Society
Place of Publication: [Washington, D.C.]
Date(s):
  • Creation: March 10, 2005
Description:

Article discussing the thermodynamic, kinetic, and mechanism of (silox)3M(olefin) to (silox)3M(alkylidene) rearrangements (silox = tBu3SiO; M = Nb, Ta).

Degree:
Department: Chemistry
Note:

Reprinted with permission from the Journal of the American Chemical Society. Copyright 2005 American Chemical Society.

Note:

Abstract: Olefin complexes (silox)3M(ole) (silox = tBu3SiO; M = Nb (1-ole), Ta (2-ole); ole = C2H4, C2H3Me, C2H3Et, C2H3C6H4-p-X (X = OMe, H, CF₃), C₂H3tBu, cC5H8, cC6H10, cC7H10 (norbornene)) rearrange to alkylidene isomers (silox)3M(alk) (M = Nb (1=alk), Ta (2=alk); alk = CHMe, CHEt, CHnPr, CHCH2C6H4-p-X (X = OMe, H, CF3 (Ta only)), CHCH2tBu, cC5H8, cC6H10, cC7H10 (norbornylidene)). Kinetics and labeling experiments suggest that the rearrangement proceeds via a ơ-abstraction on a silox CH bond by the β-olefin carbon to give (silox)2RM(κ2-O,C-OSitBu2CMe2CH2) (M = Nb (4-R), Ta (6-R); R = Me, Et, nPr, nBu, CH2-CH2C6H4-p-X (X = OMe, H, CF3 (Ta only)), CH2CH2tBu, cC5H9, cC6H11, cC7H11 (norbornyl)). A subsequent α-abstraction by the cylometalated "arm" of the intermediate on an α-CH bond of R generates the alkylidene 1=alk or 2=alk. Equilibrations of 1-ole with ole' to give 1-ole' and ole, and relevant calculations on 1-ole and 2-ole, permit interpretation of all relative ground and transition state energies for the complexes of either metal.

Physical Description:

22 p.

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Subject(s):
Keyword(s): thermodynamics | kinetics | mechanisms | complexes
Source: Journal of the American Chemical Society, 2005, Washington DC: American Chemical Society, pp. 4809-4830
Partner:
UNT College of Arts and Sciences
Collection:
UNT Scholarly Works
Identifier:
  • DOI: 10.1021/ja046180k
  • ARK: ark:/67531/metadc77135
Resource Type: Article
Format: Text
Rights:
Access: Public
Citation:
Publication Title: Journal of the American Chemical Society
Volume: 127
Page Start: 4809
Page End: 4830
Peer Reviewed: Yes