Silylation of aromatic heterocycles by earth abundant transition-metal-free catalysts

Patent metadata

Field	Value
Publication number	US-9809607-B2
Application number	US-201514818417-A
Country	US
Kind code	B2
Filing date	Aug 5, 2015
Priority date	Aug 6, 2014
Publication date	Nov 7, 2017
Grant date	Nov 7, 2017

Abstract

The present invention describes chemical systems and methods for silylating aromatic organic substrates, said system or method comprising or consisting essentially of a mixture of (a) at least one organosilane and (b) at least one strong base, the definition of strong base now also including KOH, said system being preferably, but not necessarily substantially free of a transition-metal compound, and said methods comprising contacting a quantity of the organic substrate with a mixture of (a) at least one organosilane and (b) at least one strong base, under conditions sufficient to silylate the aromatic substrate.

First claim

What is claimed:

1. A method comprising contacting an organic substrate comprising an aromatic moiety with a mixture comprising (a) at least one hydrosilane and (b) potassium hydroxide (KOH), under conditions sufficient to silylate the organic substrate, the method resulting in the formation of a silylated organic substrate, wherein the silylated organic substrate has a carbon-silicon bond in a position corresponding to a position on the aromatic moiety having a carbon-hydrogen bond, unless:
(a) the aromatic moiety is an aryl moiety having an alkyl substituent, in which case the silylated organic substrate has a carbon-silicon bond on the carbon alpha to the aryl moiety; or
(b) the aromatic moiety is one having an alkylthioether substituent, in which case the silylated organic substrate has a carbon-silicon bond on the carbon alpha to the thioether sulfur; or
(c) the aromatic moiety is a pyridinyl moiety having alkyl substituents on one or both C2-and C6-positions, in which case the silylated organic substrate has a carbon-silicon bond on the carbon alpha to the pyridinyl ring; or
(d) the aromatic moiety is a heteroaryl moiety comprising a 5-membered heteroaryl ring having no C—H substituents in its C-2 or C-5 position and at least one alkyl substituent in the C-2 or C-5 position, in which case the silylated organic substrate has a carbon-silicon bond on the carbon alpha to the 5-membered heteroaryl ring.

2. The method of claim 1 , wherein the mixture and organic substrate are free of added transition-metal species.

3. The method of claim 1 , wherein the at least one hydrosilane comprises a hydrosilane of Formula (I) or Formula (II):
(R) 4-m Si(H) m   (I)

R—[—SiH(R)—O—] n —R  (II)

where m is 1, 2, or 3;
n is 10 to 100; and
each R is independently optionally substituted C 1-12 alkyl or C 1-12 heteroalkyl, optionally substituted C 6-20 aryl or C 5-20 heteroaryl, optionally substituted C 7-30 alkaryl or C 6-30 heteroalkaryl, optionally substituted C 7-30 aralkyl or C 6-30 heteroaralkyl, optionally substituted —O—C 1-12 alkyl or —O— C 1-12 heteroalkyl, optionally substituted —O—C 7-20 aryl or —O—C 5-20 heteroaryl, optionally substituted —O—C 7-30 alkaryl or —O—C 6-30 heteroalkaryl, or optionally substituted —O—C 7-30 aralkyl or —O—C 6-30 heteroaralkyl, and, if substituted, the substituents may be phosphonato, phosphoryl, phosphanyl, phosphino, sulfonato, C 1 -C 20 alkylsulfanyl, C 6-20 arylsulfanyl, C 1 -C 20 alkylsulfonyl, C 6-20 arylsulfonyl, C 1 -C 20 alkylsulfinyl, C 6-20 arylsulfinyl, sulfonamido, amino, amido, imino, nitro, nitroso, hydroxyl, C 1 -C 20 alkoxy, C 6-20 aryloxy, C 2 -C 20 alkoxycarbonyl, C 5 -C 20 aryloxycarbonyl, carboxyl, carboxylato, mercapto, formyl, C 1 -C 20 thioester, cyano, cyanato, thiocyanato, isocyanate, thioisocyanate, carbamoyl, epoxy, styrenyl, silyl, silyloxy, silanyl, siloxazanyl, boronato, boryl, or halogen, or a metal-containing or metalloid-containing group, where the metalloid is Sn or Ge, or where the substituents optionally provide a tether to an insoluble or sparingly soluble support media comprising alumina, silica, or carbon.

4. The method of claim 1 , wherein the at least one hydrosilane is (R) 3 SiH, where each R is independently C 1-6 alkyl.

5. The method of claim 1 , wherein the aromatic moiety contains a methyl substituent, and the silylated organic substrate has a carbon-silicon bond in a position corresponding to a carbon-hydrogen bond of the methyl substituent.

6. The method of claim 1 , wherein the aromatic moiety comprises an exocyclic aromatic methyl thioether, and the silylated organic substrate has a carbon-silicon bond on the thioether methyl substituent.

7. The method of claim 1 , wherein the organic substrate comprises a heteroaryl moiety.

8. The method of claim 7 , wherein the organic substrate comprises an optionally substituted furan, pyrrole, thiophene, pyrazole, imidazole, benzofuran, benzopyrrole, benzothiophene, indole, azaindole, dibenzofuran, xanthene, dibenzopyrrole, or dibenzothiophene.

9. The method of claim 1 , wherein the organic substrate comprises at least one of the following aromatic moieties:

where X is N—R″, O, or S;
Y is H, N(R″) 2 , O—R″, or S—R″;
p is 0 to 3;
R′ is alkyl, halo, sulfhydryl, alkoxy, aryloxy, aralkyloxy, alkaryloxy, acyl, acyloxy, alkoxycarbonyl, aryloxycarbonyl, halocarbonyl, alkylcarbonato, arylcarbonato, carboxylato (—COO—), dialkyl-substituted carbamoyl, di-haloalkyl-substituted carbamoyl, di aryl-substituted carbamoyl, di-alkyl-substituted thiocarbamoyl, di-aryl-substituted thiocarbamoyl, di-N-alkyl,N-aryl-substituted thiocarbamoyl, cyano, cyanato, thiocyanato, di-alkyl-substituted amino, di-aryl-substituted amino, arylimino (—CR═N(aryl), where R=alkyl, aryl, alkaryl, or aralkyl), nitro, nitroso, alkylsulfanyl, arylsulfanyl, alkylsulfinyl, arylsulfinyl, alkyl sulfonyl, boronato (—B(OR) 2 where R is alkyl or other hydrocarbyl); or (R′) p comprises an optionally substituted fused methylene linked diether, ethylene linked diether, or propylene linked diether, aryl, or heteroaryl moiety; and
R″ is an amine protecting group or an optionally substituted alkyl, aryl, heteroaryl, alkaryl or alk-heteroaryl.

10. The method of claim 1 , wherein the organic substrate comprises at least one of the following aromatic moieties:

where X is N—R″, O, or S;
p is 0 to 3;
R′ is alkyl, halo, sulfhydryl, alkoxy, aryloxy, aralkyloxy, alkaryloxy, acyl, acyloxy, alkoxycarbonyl, aryloxycarbonyl, halocarbonyl, alkylcarbonato, arylcarbonato, carboxylato (—COO—), dialkyl-substituted carbamoyl, di haloalkyl-substituted carbamoyl, di aryl-substituted carbamoyl, di-alkyl-substituted thiocarbamoyl, di-aryl-substituted thiocarbamoyl, di-N-alkyl,N-aryl-substituted thiocarbamoyl, cyano, cyanato, thiocyanato, di-alkyl-substituted amino, di-aryl-substituted amino, arylimino (—CR═N(aryl), where R=alkyl, aryl, alkaryl, or aralkyl), nitro, nitroso, alkylsulfanyl, arylsulfanyl, alkylsulfinyl, arylsulfinyl, alkyl sulfonyl, boronato (—B(OR) 2 where R is alkyl or other hydrocarbyl); or (R′) p comprises an optionally substituted fused methylene linked diether, ethylene linked diether, or propylene linked diether, aryl, or heteroaryl moiety.

11. The method of claim 9 , wherein the organic substrate comprises a heteroaryl moiety of structure:

where p is 1 or 2 and the silylation occurs at the C-2 position of the heteroaryl ring, unless p is 2, and R′ is alkyl located in the C-2 and C-5 positions, in which case the silylation occurs at a carbon alpha to the heteroaryl ring.

12. The method of claim 10 , wherein the organic substrate comprises a heteroaryl moiety of structure:

where p is 1 or 2 and the silylation occurs at the C-2 position of the 5-membered heteroaryl ring unless R′ is an alkyl located at the C-2 position of the 5-membered heteroaryl ring, in which case the silylation occurs at the alpha carbon located in the C-2 position of the 5-membered heteroaryl ring.

13. The method of claim 1 , wherein the organic substrate is polymeric, oligomeric, or a polymeric precursor.

14. The method of claim 1 , wherein the silylated organic substrate is further reacted under conditions sufficient to cou

Assignees

• California Inst Of Techn

Inventors

• Toutov Anton
• Betz Kerry
• Fedorov Alexey
• Stoltz Brian M
• Liu Wenbo
• Grubbs Robert H

Classifications

• C07F7/0832

  Other preparations · CPC title

• C07D209/12

  Radicals substituted by oxygen atoms · CPC title

• C07F7/0801 Primary

  General processes · CPC title

• C07F7/0827

  Syntheses with formation of a Si-C bond · CPC title