Stereochemical analysis of 1,1,2,2-tetraarylethanes. 1. Static stereochemistry

Paolo Finocchiaro, Devens Gust, W. Douglas Hounshell, John P. Hummel, Pietro Maravigna, Kurt Mislow

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Empirical force field calculations on 1,1,2,2-tetraphenylethane (TPE) and 1,1,2,2-tetrakis(2,6-xylyl)ethane (TXE) show that these molecules adopt a C2 ground-state conformation in which the methine hydrogens are in anti positions. The dihedral angles of all four rings are equally signed; these systems can therefore be viewed as four-bladed molecular propellers. Comparison of the geometric parameters for TPE and TXE reveals that TXE is a highly strained molecule, as demonstrated by the unusual elongation of the central C-C bond and the unusual enlargement of the central C-C-C angles. The 1H NMR spectra of tetramesitylethane (TME) and 1,2-dimesityl-1,2-bis(2,4,6-trimethoxyphenyl)ethane (2) at the slow exchange limit are also consistent with a C2 conformation in solution. The racemic and meso forms of 2 have been separated and configurations have been assigned to the two stereoisomers on the basis of their NMR spectra. Treatment of the static stereochemistry of 1,1,2,2-tetraarylethanes in terms of a group theoretical approach leads to a description of the full permutation-inversion group, to the calculation of the number of isomers for any given substitution pattern in such systems, and to the recognition of systems which are stereochemically correspondent to 1,1,2,2-tetraarylethanes.

Original languageEnglish (US)
Pages (from-to)4945-4952
Number of pages8
JournalJournal of the American Chemical Society
Volume98
Issue number16
StatePublished - 1976
Externally publishedYes

Fingerprint

Stereochemistry
Ethane
Conformations
Nuclear magnetic resonance
Molecules
Stereoisomerism
Propellers
Dihedral angle
Isomers
Ground state
Elongation
Hydrogen
Substitution reactions
Proton Magnetic Resonance Spectroscopy

ASJC Scopus subject areas

  • Chemistry(all)

Cite this

Finocchiaro, P., Gust, D., Hounshell, W. D., Hummel, J. P., Maravigna, P., & Mislow, K. (1976). Stereochemical analysis of 1,1,2,2-tetraarylethanes. 1. Static stereochemistry. Journal of the American Chemical Society, 98(16), 4945-4952.

Stereochemical analysis of 1,1,2,2-tetraarylethanes. 1. Static stereochemistry. / Finocchiaro, Paolo; Gust, Devens; Hounshell, W. Douglas; Hummel, John P.; Maravigna, Pietro; Mislow, Kurt.

In: Journal of the American Chemical Society, Vol. 98, No. 16, 1976, p. 4945-4952.

Research output: Contribution to journalArticle

Finocchiaro, P, Gust, D, Hounshell, WD, Hummel, JP, Maravigna, P & Mislow, K 1976, 'Stereochemical analysis of 1,1,2,2-tetraarylethanes. 1. Static stereochemistry', Journal of the American Chemical Society, vol. 98, no. 16, pp. 4945-4952.
Finocchiaro P, Gust D, Hounshell WD, Hummel JP, Maravigna P, Mislow K. Stereochemical analysis of 1,1,2,2-tetraarylethanes. 1. Static stereochemistry. Journal of the American Chemical Society. 1976;98(16):4945-4952.
Finocchiaro, Paolo ; Gust, Devens ; Hounshell, W. Douglas ; Hummel, John P. ; Maravigna, Pietro ; Mislow, Kurt. / Stereochemical analysis of 1,1,2,2-tetraarylethanes. 1. Static stereochemistry. In: Journal of the American Chemical Society. 1976 ; Vol. 98, No. 16. pp. 4945-4952.
@article{7211db307bf946adb7f55ee2039dc8d1,
title = "Stereochemical analysis of 1,1,2,2-tetraarylethanes. 1. Static stereochemistry",
abstract = "Empirical force field calculations on 1,1,2,2-tetraphenylethane (TPE) and 1,1,2,2-tetrakis(2,6-xylyl)ethane (TXE) show that these molecules adopt a C2 ground-state conformation in which the methine hydrogens are in anti positions. The dihedral angles of all four rings are equally signed; these systems can therefore be viewed as four-bladed molecular propellers. Comparison of the geometric parameters for TPE and TXE reveals that TXE is a highly strained molecule, as demonstrated by the unusual elongation of the central C-C bond and the unusual enlargement of the central C-C-C angles. The 1H NMR spectra of tetramesitylethane (TME) and 1,2-dimesityl-1,2-bis(2,4,6-trimethoxyphenyl)ethane (2) at the slow exchange limit are also consistent with a C2 conformation in solution. The racemic and meso forms of 2 have been separated and configurations have been assigned to the two stereoisomers on the basis of their NMR spectra. Treatment of the static stereochemistry of 1,1,2,2-tetraarylethanes in terms of a group theoretical approach leads to a description of the full permutation-inversion group, to the calculation of the number of isomers for any given substitution pattern in such systems, and to the recognition of systems which are stereochemically correspondent to 1,1,2,2-tetraarylethanes.",
author = "Paolo Finocchiaro and Devens Gust and Hounshell, {W. Douglas} and Hummel, {John P.} and Pietro Maravigna and Kurt Mislow",
year = "1976",
language = "English (US)",
volume = "98",
pages = "4945--4952",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "16",

}

TY - JOUR

T1 - Stereochemical analysis of 1,1,2,2-tetraarylethanes. 1. Static stereochemistry

AU - Finocchiaro, Paolo

AU - Gust, Devens

AU - Hounshell, W. Douglas

AU - Hummel, John P.

AU - Maravigna, Pietro

AU - Mislow, Kurt

PY - 1976

Y1 - 1976

N2 - Empirical force field calculations on 1,1,2,2-tetraphenylethane (TPE) and 1,1,2,2-tetrakis(2,6-xylyl)ethane (TXE) show that these molecules adopt a C2 ground-state conformation in which the methine hydrogens are in anti positions. The dihedral angles of all four rings are equally signed; these systems can therefore be viewed as four-bladed molecular propellers. Comparison of the geometric parameters for TPE and TXE reveals that TXE is a highly strained molecule, as demonstrated by the unusual elongation of the central C-C bond and the unusual enlargement of the central C-C-C angles. The 1H NMR spectra of tetramesitylethane (TME) and 1,2-dimesityl-1,2-bis(2,4,6-trimethoxyphenyl)ethane (2) at the slow exchange limit are also consistent with a C2 conformation in solution. The racemic and meso forms of 2 have been separated and configurations have been assigned to the two stereoisomers on the basis of their NMR spectra. Treatment of the static stereochemistry of 1,1,2,2-tetraarylethanes in terms of a group theoretical approach leads to a description of the full permutation-inversion group, to the calculation of the number of isomers for any given substitution pattern in such systems, and to the recognition of systems which are stereochemically correspondent to 1,1,2,2-tetraarylethanes.

AB - Empirical force field calculations on 1,1,2,2-tetraphenylethane (TPE) and 1,1,2,2-tetrakis(2,6-xylyl)ethane (TXE) show that these molecules adopt a C2 ground-state conformation in which the methine hydrogens are in anti positions. The dihedral angles of all four rings are equally signed; these systems can therefore be viewed as four-bladed molecular propellers. Comparison of the geometric parameters for TPE and TXE reveals that TXE is a highly strained molecule, as demonstrated by the unusual elongation of the central C-C bond and the unusual enlargement of the central C-C-C angles. The 1H NMR spectra of tetramesitylethane (TME) and 1,2-dimesityl-1,2-bis(2,4,6-trimethoxyphenyl)ethane (2) at the slow exchange limit are also consistent with a C2 conformation in solution. The racemic and meso forms of 2 have been separated and configurations have been assigned to the two stereoisomers on the basis of their NMR spectra. Treatment of the static stereochemistry of 1,1,2,2-tetraarylethanes in terms of a group theoretical approach leads to a description of the full permutation-inversion group, to the calculation of the number of isomers for any given substitution pattern in such systems, and to the recognition of systems which are stereochemically correspondent to 1,1,2,2-tetraarylethanes.

UR - http://www.scopus.com/inward/record.url?scp=0010852090&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0010852090&partnerID=8YFLogxK

M3 - Article

VL - 98

SP - 4945

EP - 4952

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 16

ER -