ISSN:
0009-2940
Keywords:
Methyleniminium salts, preparation, mechanisms of formation
;
(Dialkylamino)trimethylsilanes
;
Ethers, α-chloro
;
Viehe salts, vinylogous
;
Chemistry
;
Inorganic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
New Syntheses of Methyleniminium Salts from Carbonyl Compounds and from α-Chloro Ethers; an Access to Vinylogous Viehe Salts*Two methods for the synthesis of isolable methyleniminium salts and amidinium salts are presented. In the first case carbonyl compounds A are treated with a mixture of (dialkyl-amino)trimethylsilane (12) and chlorotrimethylsilane (13) or 12 and trimethylsilyl triflate (14) leading to the iminium chlorides F or iminium triflates G, respectively. With 12/13 the preparation of F is limited to non-enolizable aldehydes and dimethylformamide (10), while 12/14 enables the preparation of G, e.g. 23a-25a, 27a, also with ketones and with substituted amides. The second procedure is based on the treatment of α-chloro ethers L with 12. Both methods afford the Mannich reagent 16a in high yields. By reaction of the α-chloro ether 35 with 12 in diethyl ether the vinylogous Viehe salts 36a-c, e become available for the first time. The reaction pathways are discussed.
Additional Material:
1 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/cber.19941271026
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