# US 11,028,107 B2 · Stable silylating reagents

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- Number: US 11,028,107 B2
- Document ID: US11028107B2
- Status: Granted
- Kind: B2
- Application number: 15/438,929
- Filed: 2017-02-22
- Published: 2017-08-24
- Granted: 2021-06-08
- Earliest claimed: 2016-02-22
- Assignees: California Institute of Technology
- Applicants: California Institute of Technology
- Inventors: Anton Toutov; Wenbo Liu; David P. Schuman; Brian M. Stoltz; Robert H. Grubbs
- Web page: https://patentgrep.com/patent/US11028107B2

## CPC

- C07F 7/0814: {said ring is substituted at a C ring atom by Si}
- C07F 7/0896: {Compounds with a Si-H linkage}
- C07F 7/1804: {Compounds having Si-O-C linkages (Si-O-acyl linkages C07F7/1896)}
- C07F: ACYCLIC, CARBOCYCLIC OR HETEROCYCLIC COMPOUNDS CONTAINING ELEMENTS OTHER THAN CARBON, HYDROGEN, HALOGEN, OXYGEN, NITROGEN, SULFUR, SELENIUM OR TELLURIUM (metal-containing porphyrins C07D487/22)

## Abstract

The present invention is directed to compositions for silylating organic substrates containing C—H or O—H bonds, especially heteroaromatic substrates. The compositions are derived from the preconditioning of mixtures of hydrosilanes or organodisilanes with bases, including metal hydroxide and metal alkoxide bases. In some embodiments, the preconditioning results in the formation of reactive silicon hydride species.

## Claims

### Claim 1

A solution composition prepared by preconditioning a mixture of:
(a) a precursor hydrosilane; and
(b) a base comprising potassium hydroxide, a potassium alkoxide, a potassium silanolate, rubidium hydroxide, a rubidium alkoxide, a rubidium silanolate, cesium hydroxide, a cesium alkoxide, a cesium silanolate, a potassium amide, or a combination thereof; in
(c) a preconditioning solvent comprising one or more tetrahydrofurans, wherein the preconditioning solvent comprises 2-methyl-tetrahydrofuran;
in the absence of any heteroaromatic, olefinic, or acetylenic substrates capable of C—H silylation, or any alcohol substrates; wherein
the solution composition contains a species formed by the preconditioning of the mixture of (a) and (b) in the preconditioning solvent, wherein the species is present in sufficient amount to exhibit an observable infrared absorption peak in an Si—H stretching region of an infrared spectrum, that infrared absorption peak being of lower energy than a corresponding Si—H absorption peak of the precursor hydrosilane, when evaluated under comparable conditions; and wherein
(i) the solution composition comprises the preconditioning solvent comprising one or more tetrahydrofurans, wherein the preconditioning solvent comprises 2-methyl-tetrahydrofuran, and is free of any added heteroaromatic, olefinic, or acetylenic substrates capable of C—H silylation by the pre-conditioned mixture, or of any added alcohol substrates;
(ii) the preconditioning comprises holding the mixture of combined hydrosilane and the base in the preconditioning solvent under conditions sufficient to produce the solution composition, which is capable of initiating measurable silylation of 1-methyl indole at a temperature of 45° C. or less with an induction period of less than 30 minutes;
(iii) the precursor hydrosilane is of the Formula (I) or Formula (II):
(R)3−mSi(H)m+1 (I)
(R)3−m(H)mSi—Si(R)2−m(H)m+1 (II)
where: m is independently 0, 1, or 2; and each R is independently optionally substituted C1-24 alkyl, optionally substituted C2-24 alkenyl, optionally substituted C2-24 alkynyl, optionally substituted C6-12 aryl, C3-12 heteroaryl, optionally substituted C7-13 alkaryl, optionally substituted C4-12 heteroalkaryl, optionally substituted C7-13 aralkyl, optionally substituted C4-12 heteroaralkyl, and, if substituted, the substituents are independently nitro, C1-C20 alkoxy, C5-C20 aryloxy, or halogen.

### Claim 2 (depends on 1)

The solution composition of claim 1, wherein the base comprises potassium hydroxide, rubidium hydroxide, or cesium hydroxide.

### Claim 3 (depends on 1)

The solution composition of claim 1, wherein the base comprises potassium hydroxide.

### Claim 4 (depends on 1)

The solution composition of claim 1, wherein the base comprises a potassium alkoxide, a rubidium alkoxide, or a cesium alkoxide.

### Claim 5 (depends on 1)

The solution composition of claim 1, wherein the base comprises a potassium alkoxide.

### Claim 6 (depends on 1)

The solution composition of claim 1, wherein the base comprises a potassium tert-butoxide.

### Claim 7 (depends on 1)

The solution composition of claim 1, wherein the base comprises a potassium amide.

### Claim 8 (depends on 1)

The solution composition of claim 1, wherein the precursor hydrosilane is of the Formula (I) or Formula (II):
(R)3−mSi(H)m+1 (I)
(R)3−m(H)mSi—Si(R)2−m(H)m+1 (II)
where: m is independently 0, 1, or 2; and each R is independently C1-24 alkyl, C2-24 alkenyl, C2-24 alkynyl, C6-12 aryl, C3-12 heteroaryl, C7-13 alkaryl, C4-12 heteroalkaryl, C7-13 aralkyl, or C4-12 heteroaralkyl.

### Claim 9 (depends on 1)

The solution composition of claim 1, wherein the hydrosilane is (R)3SiH or (R)2SiH2, where R is independently at each occurrence C1-6 alkyl, phenyl, tolyl, or pyridinyl.

### Claim 10 (depends on 9)

The solution composition of claim 9, wherein the base comprises potassium tert-butoxide.

### Claim 11 (depends on 1)

The solution composition of claim 1, wherein the solution composition contains less than 50 ppm of a transition metal catalyst.

### Claim 12 (depends on 1)

The solution composition of claim 1, wherein the solution composition contains less than 10 ppm of a transition metal catalyst.

### Claim 13 (depends on 1)

The solution composition of claim 1, wherein the species present in sufficient amount to exhibit an infrared absorption peak in the Si—H stretching region of an infrared spectrum comprises a Si—H—based species derived from the preconditioning of the mixture of:
(a) the precursor hydrosilane; and
(b) the base comprising potassium hydroxide, a potassium alkoxide, a potassium silanolate, rubidium hydroxide, a rubidium alkoxide, a rubidium silanolate, cesium hydroxide, a cesium alkoxide, a cesium silanolate, or a combination thereof; in
(c) the preconditioning solvent comprising one or more tetrahydrofurans, wherein the preconditioning solvent comprises 2-methyl-tetrahydrofuran;
wherein the solution composition is free of any added heteroaromatic, olefinic, or acetylenic substrates capable of C—H silylation, or of any alcohol substrates; and
wherein the Si—H—based species is present in the preconditioning solvent in sufficient amount to exhibit an absorption peak in the Si—H stretching region of an infrared spectrum that is of lower energy than a corresponding absorption peak of the precursor hydrosilane, when evaluated under comparable conditions.

### Claim 14 (depends on 13)

The solution composition of claim 13, wherein the preconditioning solvent is 2-methyl-tetrahydrofuran.

### Claim 15 (depends on 2)

The solution composition of claim 2, wherein the Si—H—based species derived from the preconditioning of the mixture comprises an optionally solvated silicon hydride structure of Formula (IV):
or a geometric isomer thereof, wherein
M+is a cation comprising potassium, rubidium, cesium, or a combination thereof;
—ORB is hydroxide, an alkoxide, an alkyl silanolate; or a combination thereof; and
—RS is H, —R, or Si(R)3−mHm, or a combination thereof
wherein m is independently 0, 1, or 2; and each R is independently C1-24 alkyl, C2-24 alkenyl, C2-24 alkynyl, C6-12 aryl, C3-12 heteroaryl, C7-13 alkaryl, C4-12 heteroalkaryl, C7-13 aralkyl, or C4-12 heteroaralkyl.

### Claim 16 (depends on 13)

The solution composition of claim 13, wherein the solution composition contains less than 50 ppm of a transition metal catalyst.

### Claim 17 (depends on 13)

The solution composition of claim 13, wherein the solution composition contains less than 10 ppm of a transition metal catalyst.