Regioselective, stereoselective, and conformationally controlled synthesis of (η4-tetraarylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes

Doyle J. Cassar; Elisabeth Nagaradja; David C. D. Butler; Didier Villemin; Christopher J. Richards

doi:10.1021/ol203415r

Regioselective, stereoselective, and conformationally controlled synthesis of (η4-tetraarylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes

Doyle J. Cassar, Elisabeth Nagaradja, David C. D. Butler, Didier Villemin, Christopher J. Richards

Research output: Contribution to journal › Article › peer-review

9 Citations (Scopus)

Abstract

The Friedel–Crafts reaction of (η4-tetraphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt with acid chlorides/aluminum chloride resulted exclusively in para-phenyl acylation. Both monoacylated (1.1 equiv of RCOCl/AlCl3) and tetraacylated products (>4 equiv of RCOCl/AlCl3) were synthesized. Reaction of PhCC(o-RC6H4) (R = Me, i-Pr) with Na(C5H4CO2Me) and CoCl(PPh3)3 gave predominantly (η4-1,3-diaryl-2,4-diphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes (1,3-[trans] vs 1,2-[cis] selectivity up to 6:1). Conformational control of Friedel–Crafts reactions on the major isomers gave exclusively para-acylation of the unsubstituted phenyl groups.

Original language	English
Pages (from-to)	894-897
Number of pages	4
Journal	Organic Letters
Volume	14
Issue number	3
DOIs	https://doi.org/10.1021/ol203415r
Publication status	Published - 2012

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10.1021/ol203415r

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@article{8bea43c614364274919dcace16c8e1d5,

title = "Regioselective, stereoselective, and conformationally controlled synthesis of (η4-tetraarylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes",

abstract = "The Friedel–Crafts reaction of (η4-tetraphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt with acid chlorides/aluminum chloride resulted exclusively in para-phenyl acylation. Both monoacylated (1.1 equiv of RCOCl/AlCl3) and tetraacylated products (>4 equiv of RCOCl/AlCl3) were synthesized. Reaction of PhCC(o-RC6H4) (R = Me, i-Pr) with Na(C5H4CO2Me) and CoCl(PPh3)3 gave predominantly (η4-1,3-diaryl-2,4-diphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes (1,3-[trans] vs 1,2-[cis] selectivity up to 6:1). Conformational control of Friedel–Crafts reactions on the major isomers gave exclusively para-acylation of the unsubstituted phenyl groups.",

author = "Cassar, {Doyle J.} and Elisabeth Nagaradja and Butler, {David C. D.} and Didier Villemin and Richards, {Christopher J.}",

year = "2012",

doi = "10.1021/ol203415r",

language = "English",

volume = "14",

pages = "894--897",

journal = "Organic Letters",

issn = "1523-7060",

publisher = "American Chemical Society",

number = "3",

}

TY - JOUR

T1 - Regioselective, stereoselective, and conformationally controlled synthesis of (η4-tetraarylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes

AU - Cassar, Doyle J.

AU - Nagaradja, Elisabeth

AU - Butler, David C. D.

AU - Villemin, Didier

AU - Richards, Christopher J.

PY - 2012

Y1 - 2012

N2 - The Friedel–Crafts reaction of (η4-tetraphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt with acid chlorides/aluminum chloride resulted exclusively in para-phenyl acylation. Both monoacylated (1.1 equiv of RCOCl/AlCl3) and tetraacylated products (>4 equiv of RCOCl/AlCl3) were synthesized. Reaction of PhCC(o-RC6H4) (R = Me, i-Pr) with Na(C5H4CO2Me) and CoCl(PPh3)3 gave predominantly (η4-1,3-diaryl-2,4-diphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes (1,3-[trans] vs 1,2-[cis] selectivity up to 6:1). Conformational control of Friedel–Crafts reactions on the major isomers gave exclusively para-acylation of the unsubstituted phenyl groups.

AB - The Friedel–Crafts reaction of (η4-tetraphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt with acid chlorides/aluminum chloride resulted exclusively in para-phenyl acylation. Both monoacylated (1.1 equiv of RCOCl/AlCl3) and tetraacylated products (>4 equiv of RCOCl/AlCl3) were synthesized. Reaction of PhCC(o-RC6H4) (R = Me, i-Pr) with Na(C5H4CO2Me) and CoCl(PPh3)3 gave predominantly (η4-1,3-diaryl-2,4-diphenylcyclobutadiene)(η5-carbomethoxycyclopentadienyl)cobalt metallocenes (1,3-[trans] vs 1,2-[cis] selectivity up to 6:1). Conformational control of Friedel–Crafts reactions on the major isomers gave exclusively para-acylation of the unsubstituted phenyl groups.

U2 - 10.1021/ol203415r

DO - 10.1021/ol203415r

M3 - Article

SN - 1523-7060

VL - 14

SP - 894

EP - 897

JO - Organic Letters

JF - Organic Letters

IS - 3

ER -