- Organylthio(silyl)carbenes
-
The title carbenes 5 can be generated either from diazo compounds 9 by copper-catalyze d catalysis or from chloro(organylthio)methylsilanes 12 by base-induced α-elimination, This is confirmed, by [2+1] cycloadditions with alkenes to give the cyclopropanes
- Wagner, Tobias,Lange, Jens,Grote, Dirk,Sander, Wolfram,Schaumann, Ernst,Adiwidjaja, Gunadi,Adam, Arnold,Kopf, Juergen
-
experimental part
p. 5198 - 5207
(2010/01/11)
-
- Carbonium Ion Rearrangements Controlled by the Presence of a Silyl Group
-
γ-Silyl tertiary alcohols rearrange in protic acid with 1,2-shift of hydride, phenyl, or alkyl groups, and loss of the silyl group to give alkenes.The placing of the silyl group thus controls the carbonium ion rearrangement in a preparatively useful way.Methoxycarbonyl groups do not migrate; instead, cyclopropanes are formed, except when the conformation suitable for cyclopropane formation is unattainable.When the alkene product is 2,2-disubstituted, it can be reprotonated under the reaction conditions and does not therefore always survive.This can be avoided by carrying out the reaction using a Lewis acid on the silyl ether.The starting γ-silyl alcohols are prepared by a variety of versatile methods.
- Fleming, Ian,Patel, Shailesh K.,Urch, Christopher J.
-
p. 115 - 124
(2007/10/02)
-
- α-ALKYLATION AND α-ALKYLIDENATION OF CARBONYL COMPOUNDS BY O-SILYLATED ENOLATE PHENYLTHIOALKYLATION
-
For many reactions next to a carbonyl group, the use of O-silylated enolate chemistry offers improvements in yield and selectivity over the corresponding reactions of Group I metal enolates.In the case of α-alkylation of carbonyl compounds, Lewis acid (TiCl4 or ZnBr2) promoted phenylthioalkylation of O-silylated enolates 3 by α-chlorosulphides 4 (R3=H, Me, Prn, Pri, Bui, and Me3Si), followed by reductive sulphur removal by Raney nickel, 5->6, is found to be a reliable method for this synthetically important C-C bond forming step.An alternative sulphur elimination pathway via the sulphoxide, 5->7, allows the regio- and stereocontrolled α-alkylidenation of carbonyl compounds.The phenylthioalkylation reaction is applicable to ketones, aldehydes, esters, and lactones.
- Paterson, Ian
-
p. 4207 - 4220
(2007/10/02)
-
- Reaction of trimethylsilanes with Arenes and Alk-1-enes in the Presence of Lewis Acid: Syntheses of - and (1-Arylthioalk-3-enyl)-trimethylsilanes
-
Treatment of equimolar amounts of the trimethylsilanes (2) or (3) and electron-rich arenes with an equimolar amount of Lewis acid (SnCl4 or TiCl4) gave the Friedel-Crafts reaction products, trimethylsilanes (4) or (5), in high yields.Similar treatment of the chlorides (2) or (3) with alk-1-enes gave ene type products, trimethylsilanes (12) or (13), in moderate yields.Some chemical transformations of these products are also described.
- Ishibashi, Hiroyuki,Nakatani, Hiroshi,Umei, Yoshizumi,Yamamoto, Wako,Ikeda, Masazumi
-
p. 589 - 594
(2007/10/02)
-
- INTRODUCTION OF AN ARYLTHIO(TRIMETHYLSILYL)METHYL GROUP INTO ARENES BY FRIEDEL-CRAFTS REACTION: SYNTHESIS OF ARYLMETHYLTRIMETHYLSILANES
-
Friedel-Crafts reactions of trimethylsilanes (1a, b) with arenes gave trimethylsilanes (2a,b), which were converted into arylmethyltrimethylsilanes (3) by reduction with Raney nickel.
- Ishibashi, Hiroyuki,Nakatani, Hiroshi,Umei, Yoshizumi,Ikeda, Masazumi
-
p. 4373 - 4374
(2007/10/02)
-
- Chloro(phenylthio)methyltrimethylsilane: Preparation and some Synthetic Reactions
-
Reaction of the title compound (2) with lead thiocyanate gave phenylthio(trimethylsilyl)methyl isothiocyanate (3) which further reacted with aromatic aldehydes in the presence of fluoride ion to afford oxazoles in good yields.Compound (2) also reacted with silyl enol ethers to give β-silyl ketones which were capable of being converted into β-functionalized vinylsilanes.
- Yamamoto, Iwao,Okuda, Kazuhide,Nagai, Shigemasa,Motoyoshiya, Jiro,Gotoh, Haruo,Matsuzaki, Kei
-
p. 435 - 438
(2007/10/02)
-