The polyhomologation of 1-boraadamantane: Mapping the migration pathways of a propagating macrotricyclic trialkylborane

Carl Wagner, Jang Seob Kim, Kenneth J. Shea

Research output: Contribution to journalArticle

54 Citations (Scopus)

Abstract

Trialkyl and triaryl organoboranes undergo multiple, repetitive homologations upon reaction with dimethylsulfoxonium methylide (1). This multiple homologation reaction, or polyhomologation, produces polymethylene in a living reaction. Applying the polyhomologation reaction to cyclic and polycyclic organoboranes permits the construction of unique oligomeric and polymeric architectures that are not readily accessible by standard olefin polymerization. The polyhomologation of 1-boraadamantane-THF (2) by ylide 1 generates novel macrotricyclic trialkylboranes (3). The oxidation of these macrocyclic organoboranes generates a three-armed star polymethylene polymer (4) incorporating a cis, cis-1,3,5-trisubstituted cyclohexane core. Interestingly, only one-third of the initiators lead to product formation, resulting in an observed degree of polymerization 3 times higher than expected. Close examination of the initial stages of polymerization show that 1-boraadamantane-THF reacts with 1 equiv of 1 to afford a monohomologated product. Subsequent homologations were found to contain branch points leading to isomeric tricyclic products after the third, fourth, and fifth methylene insertions. At these stages of homologation, all of the propagating species result in tricyclic trialkylborane cages with collapsed, inverted pyramidal boron centers that are substantially less reactive toward ylide. Approximately two-thirds of the species discontinue polymerization at these stages. However, one-third of these species continue to propagate and eventually result in the formation of giant macrotricyclic polymers of narrow polydispersity. Molecular modeling and kinetic simulation have aided in the analysis of the probable pathways through which the reaction proceeds.

Original languageEnglish (US)
Pages (from-to)12179-12195
Number of pages17
JournalJournal of the American Chemical Society
Volume125
Issue number40
DOIs
StatePublished - Oct 8 2003
Externally publishedYes

Fingerprint

Polymerization
Polymers
Boron
Molecular modeling
Polydispersity
Alkenes
Cyclohexane
Olefins
Stars
Oxidation
Kinetics

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

The polyhomologation of 1-boraadamantane : Mapping the migration pathways of a propagating macrotricyclic trialkylborane. / Wagner, Carl; Kim, Jang Seob; Shea, Kenneth J.

In: Journal of the American Chemical Society, Vol. 125, No. 40, 08.10.2003, p. 12179-12195.

Research output: Contribution to journalArticle

@article{26f90b638f374afe80e66fefa548db52,
title = "The polyhomologation of 1-boraadamantane: Mapping the migration pathways of a propagating macrotricyclic trialkylborane",
abstract = "Trialkyl and triaryl organoboranes undergo multiple, repetitive homologations upon reaction with dimethylsulfoxonium methylide (1). This multiple homologation reaction, or polyhomologation, produces polymethylene in a living reaction. Applying the polyhomologation reaction to cyclic and polycyclic organoboranes permits the construction of unique oligomeric and polymeric architectures that are not readily accessible by standard olefin polymerization. The polyhomologation of 1-boraadamantane-THF (2) by ylide 1 generates novel macrotricyclic trialkylboranes (3). The oxidation of these macrocyclic organoboranes generates a three-armed star polymethylene polymer (4) incorporating a cis, cis-1,3,5-trisubstituted cyclohexane core. Interestingly, only one-third of the initiators lead to product formation, resulting in an observed degree of polymerization 3 times higher than expected. Close examination of the initial stages of polymerization show that 1-boraadamantane-THF reacts with 1 equiv of 1 to afford a monohomologated product. Subsequent homologations were found to contain branch points leading to isomeric tricyclic products after the third, fourth, and fifth methylene insertions. At these stages of homologation, all of the propagating species result in tricyclic trialkylborane cages with collapsed, inverted pyramidal boron centers that are substantially less reactive toward ylide. Approximately two-thirds of the species discontinue polymerization at these stages. However, one-third of these species continue to propagate and eventually result in the formation of giant macrotricyclic polymers of narrow polydispersity. Molecular modeling and kinetic simulation have aided in the analysis of the probable pathways through which the reaction proceeds.",
author = "Carl Wagner and Kim, {Jang Seob} and Shea, {Kenneth J.}",
year = "2003",
month = "10",
day = "8",
doi = "10.1021/ja0361291",
language = "English (US)",
volume = "125",
pages = "12179--12195",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "40",

}

TY - JOUR

T1 - The polyhomologation of 1-boraadamantane

T2 - Mapping the migration pathways of a propagating macrotricyclic trialkylborane

AU - Wagner, Carl

AU - Kim, Jang Seob

AU - Shea, Kenneth J.

PY - 2003/10/8

Y1 - 2003/10/8

N2 - Trialkyl and triaryl organoboranes undergo multiple, repetitive homologations upon reaction with dimethylsulfoxonium methylide (1). This multiple homologation reaction, or polyhomologation, produces polymethylene in a living reaction. Applying the polyhomologation reaction to cyclic and polycyclic organoboranes permits the construction of unique oligomeric and polymeric architectures that are not readily accessible by standard olefin polymerization. The polyhomologation of 1-boraadamantane-THF (2) by ylide 1 generates novel macrotricyclic trialkylboranes (3). The oxidation of these macrocyclic organoboranes generates a three-armed star polymethylene polymer (4) incorporating a cis, cis-1,3,5-trisubstituted cyclohexane core. Interestingly, only one-third of the initiators lead to product formation, resulting in an observed degree of polymerization 3 times higher than expected. Close examination of the initial stages of polymerization show that 1-boraadamantane-THF reacts with 1 equiv of 1 to afford a monohomologated product. Subsequent homologations were found to contain branch points leading to isomeric tricyclic products after the third, fourth, and fifth methylene insertions. At these stages of homologation, all of the propagating species result in tricyclic trialkylborane cages with collapsed, inverted pyramidal boron centers that are substantially less reactive toward ylide. Approximately two-thirds of the species discontinue polymerization at these stages. However, one-third of these species continue to propagate and eventually result in the formation of giant macrotricyclic polymers of narrow polydispersity. Molecular modeling and kinetic simulation have aided in the analysis of the probable pathways through which the reaction proceeds.

AB - Trialkyl and triaryl organoboranes undergo multiple, repetitive homologations upon reaction with dimethylsulfoxonium methylide (1). This multiple homologation reaction, or polyhomologation, produces polymethylene in a living reaction. Applying the polyhomologation reaction to cyclic and polycyclic organoboranes permits the construction of unique oligomeric and polymeric architectures that are not readily accessible by standard olefin polymerization. The polyhomologation of 1-boraadamantane-THF (2) by ylide 1 generates novel macrotricyclic trialkylboranes (3). The oxidation of these macrocyclic organoboranes generates a three-armed star polymethylene polymer (4) incorporating a cis, cis-1,3,5-trisubstituted cyclohexane core. Interestingly, only one-third of the initiators lead to product formation, resulting in an observed degree of polymerization 3 times higher than expected. Close examination of the initial stages of polymerization show that 1-boraadamantane-THF reacts with 1 equiv of 1 to afford a monohomologated product. Subsequent homologations were found to contain branch points leading to isomeric tricyclic products after the third, fourth, and fifth methylene insertions. At these stages of homologation, all of the propagating species result in tricyclic trialkylborane cages with collapsed, inverted pyramidal boron centers that are substantially less reactive toward ylide. Approximately two-thirds of the species discontinue polymerization at these stages. However, one-third of these species continue to propagate and eventually result in the formation of giant macrotricyclic polymers of narrow polydispersity. Molecular modeling and kinetic simulation have aided in the analysis of the probable pathways through which the reaction proceeds.

UR - http://www.scopus.com/inward/record.url?scp=0141957598&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0141957598&partnerID=8YFLogxK

U2 - 10.1021/ja0361291

DO - 10.1021/ja0361291

M3 - Article

C2 - 14519004

AN - SCOPUS:0141957598

VL - 125

SP - 12179

EP - 12195

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 40

ER -