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Fox, Falco, Neudoerfl, Joerg M. and Goldfuss, Bernd ORCID: 0000-0002-1814-8818 (2019). Silanediol versus chlorosilanol: hydrolyses and hydrogen-bonding catalyses with fenchole-based silanes. Beilstein J. Org. Chem., 15. S. 167 - 187. FRANKFURT AM MAIN: BEILSTEIN-INSTITUT. ISSN 1860-5397

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Abstract

Biphenyl-2,2'-bisfenchyloxydichlorosilane (7, BIFOXSiC1(2)) is synthesized and employed as precursor for the new silanols biphenyl-2,2'-bisfenchyloxychlorosilanol (8, BIFOXSiC1(OH)) and biphenyl-2,2'-bisfenchyloxysilanediol (9, BIFOXSi(OH)(2)). BIFOXSiC1(2) (7) shows a remarkable stability against hydrolysis, yielding silanediol 9 under enforced conditions. A kinetic study for the hydrolysis of dichlorosilane 7 shows a 263 times slower reaction compared to reference bis-(2,4,6-tri-tert-butylphenoxy)dichlorosilane (14), known for its low hydrolytic reactivity. Computational analyses explain the slow hydrolyses of BIFOXSiC1(2) (7) to BIFOXSiC1(OH) (8, E-a = 32.6 kcal mol(-1)) and BIFOXSiC1(OH) (8) to BIFOXSi(OH)(2) (9, E-a = 31.4 kcal mol(-1)) with high activation barriers, enforced by endo fenchone units. Crystal structure analyses of silanediol 9 with acetone show shorter hydrogen bonds between the Si-OH groups and the oxygen of the bound acetone (OH center dot center dot center dot O 1.88(3)-2.05(2) angstrom) than with chlorosilanol 8 (OH center dot center dot center dot 2.16(0) angstrom). Due to its two hydroxy units, the silanediol 9 shows higher catalytic activity as hydrogen bond donor than chlorosilanol 8, e.g., C-C coupling N-acyl Mannich reaction of silyl ketene acetals 11 with N-acylisoquinolinium ions (up to 85% yield and 12% ee), reaction of 1-chloroisochroman (18) and silyl ketene acetals 11 (up to 85% yield and 5% ee), reaction of chromen-4-one (20) and silyl ketene acetals 11 (up to 98% yield and 4% ee).

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Fox, Falco UNSPECIFIED UNSPECIFIED UNSPECIFIED Neudoerfl, Joerg M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Goldfuss, Bernd UNSPECIFIED orcid.org/0000-0002-1814-8818 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-159109
DOI:	10.3762/bjoc.15.17
Journal or Publication Title:	Beilstein J. Org. Chem.
Volume:	15
Page Range:	S. 167 - 187
Date:	2019
Publisher:	BEILSTEIN-INSTITUT
Place of Publication:	FRANKFURT AM MAIN
ISSN:	1860-5397
Language:	English
Faculty:	Faculty of Mathematics and Natural Sciences
Divisions:	Faculty of Mathematics and Natural Sciences > Department of Chemistry > Institute of Organic Chemistry
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language ANION-RECOGNITION; NUCLEOPHILIC-SUBSTITUTION; ORGANOSILICON CHEMISTRY; ARYL CHLOROSILANES; SILICON-COMPOUNDS; ALKYL; IMPLEMENTATION; ADDITIONS; MECHANISM; CRYSTAL Multiple languages Chemistry, Organic Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/15910