Dinuclear titanium(IV) complex of p-tert-butylthiacalix[4]arene as a novel bidentate Lewis acid catalyst

Naoya Morohashi; Tetsutaro Hattori; Katsuya Yokomakura; Chizuko Kabuto; Sotaro Miyano

doi:10.1016/S0040-4039(02)01833-6

Dinuclear titanium(IV) complex of p-tert-butylthiacalix[4]arene as a novel bidentate Lewis acid catalyst

Naoya Morohashi, Tetsutaro Hattori, Katsuya Yokomakura, Chizuko Kabuto, Sotaro Miyano

ENG - Biomolecular Engineering

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

44 Citations (Scopus)

Abstract

Treatment of p-tert-butylthiacalix[4]arene (H₄L, 2) with TiCl₄ in dichloromethane gave two novel dinuclear titanium(IV) complexes formulated as [Ti₂LCl₄]. One of the complexes was subjected to X-ray crystallographic analysis to show that the calixarene ligand (L^4-) adopted a cone conformation, forcing the two metal centers to reside in close vicinity with syn arrangement with respect to the mean plane defined by the macrocycle (3). The other one was assigned to be an anti titanium(IV) complex (4) based on ¹H NMR spectroscopy. The syn complex showed high catalytic activity in the Mukaiyama-aldol reaction of aromatic aldehydes with silyl enol ethers, indicating the double-activation ability of the bidentate Lewis acid toward the aldehydes.

Original language	English
Pages (from-to)	7769-7772
Number of pages	4
Journal	Tetrahedron Letters
Volume	43
Issue number	43
DOIs	https://doi.org/10.1016/S0040-4039(02)01833-6
Publication status	Published - 2002 Oct 21

Keywords

Aldol reaction
Calixarene
Titanium complex
X-ray crystallographic analysis

ASJC Scopus subject areas

Biochemistry
Drug Discovery
Organic Chemistry

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10.1016/S0040-4039(02)01833-6

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title = "Dinuclear titanium(IV) complex of p-tert-butylthiacalix[4]arene as a novel bidentate Lewis acid catalyst",

abstract = "Treatment of p-tert-butylthiacalix[4]arene (H4L, 2) with TiCl4 in dichloromethane gave two novel dinuclear titanium(IV) complexes formulated as [Ti2LCl4]. One of the complexes was subjected to X-ray crystallographic analysis to show that the calixarene ligand (L4-) adopted a cone conformation, forcing the two metal centers to reside in close vicinity with syn arrangement with respect to the mean plane defined by the macrocycle (3). The other one was assigned to be an anti titanium(IV) complex (4) based on 1H NMR spectroscopy. The syn complex showed high catalytic activity in the Mukaiyama-aldol reaction of aromatic aldehydes with silyl enol ethers, indicating the double-activation ability of the bidentate Lewis acid toward the aldehydes.",

keywords = "Aldol reaction, Calixarene, Titanium complex, X-ray crystallographic analysis",

author = "Naoya Morohashi and Tetsutaro Hattori and Katsuya Yokomakura and Chizuko Kabuto and Sotaro Miyano",

note = "Funding Information: This work was supported by the JSPS Research for the Future Program. ",

year = "2002",

month = oct,

day = "21",

doi = "10.1016/S0040-4039(02)01833-6",

language = "English",

volume = "43",

pages = "7769--7772",

journal = "Tetrahedron Letters",

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T1 - Dinuclear titanium(IV) complex of p-tert-butylthiacalix[4]arene as a novel bidentate Lewis acid catalyst

AU - Morohashi, Naoya

AU - Hattori, Tetsutaro

AU - Yokomakura, Katsuya

AU - Kabuto, Chizuko

AU - Miyano, Sotaro

N1 - Funding Information: This work was supported by the JSPS Research for the Future Program.

PY - 2002/10/21

Y1 - 2002/10/21

N2 - Treatment of p-tert-butylthiacalix[4]arene (H4L, 2) with TiCl4 in dichloromethane gave two novel dinuclear titanium(IV) complexes formulated as [Ti2LCl4]. One of the complexes was subjected to X-ray crystallographic analysis to show that the calixarene ligand (L4-) adopted a cone conformation, forcing the two metal centers to reside in close vicinity with syn arrangement with respect to the mean plane defined by the macrocycle (3). The other one was assigned to be an anti titanium(IV) complex (4) based on 1H NMR spectroscopy. The syn complex showed high catalytic activity in the Mukaiyama-aldol reaction of aromatic aldehydes with silyl enol ethers, indicating the double-activation ability of the bidentate Lewis acid toward the aldehydes.

AB - Treatment of p-tert-butylthiacalix[4]arene (H4L, 2) with TiCl4 in dichloromethane gave two novel dinuclear titanium(IV) complexes formulated as [Ti2LCl4]. One of the complexes was subjected to X-ray crystallographic analysis to show that the calixarene ligand (L4-) adopted a cone conformation, forcing the two metal centers to reside in close vicinity with syn arrangement with respect to the mean plane defined by the macrocycle (3). The other one was assigned to be an anti titanium(IV) complex (4) based on 1H NMR spectroscopy. The syn complex showed high catalytic activity in the Mukaiyama-aldol reaction of aromatic aldehydes with silyl enol ethers, indicating the double-activation ability of the bidentate Lewis acid toward the aldehydes.

KW - Aldol reaction

KW - Calixarene

KW - Titanium complex

KW - X-ray crystallographic analysis

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UR - http://www.scopus.com/inward/citedby.url?scp=0037152271&partnerID=8YFLogxK

U2 - 10.1016/S0040-4039(02)01833-6

DO - 10.1016/S0040-4039(02)01833-6

M3 - Article

AN - SCOPUS:0037152271

VL - 43

SP - 7769

EP - 7772

JO - Tetrahedron Letters

JF - Tetrahedron Letters

SN - 0040-4039

IS - 43

ER -

Dinuclear titanium(IV) complex of p-tert-butylthiacalix[4]arene as a novel bidentate Lewis acid catalyst

Abstract

Keywords

ASJC Scopus subject areas

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