A Novel Route to 2-Alkoxy / Aryloxythiophenes via Simmons-Smith Reaction on Acylketene<i>O,S</i>-Acetals
作者:Laxminarayan Bhat、H. Ila、H. Junjappa
DOI:10.1055/s-1993-25978
日期:——
A novel route to 2-alkoxy/aryloxy-4-arylthiophenes 4a-k and the corresponding 3,4-annulated thiophene 7 has been developed by subjecting the respective acylketene O,S-acetals 1a-k and 6 to Simmons-Smith reaction conditions (zinc-copper/diiodomethane).
Synthesis of α-Oxoketene<i>O</i>-Alkyl/Aryl,<i>S</i>-Alkyl Acetals
作者:Makhan L. Purkayastha、Malapaka Chandrasekharam、Jai N. Vishwakarma、Hiriyakkanavar Ila、Hiriyakkanavar Junjappa
DOI:10.1055/s-1993-25841
日期:——
The synthesis of acylketene O,S-dialkyl acetals 2a-p and acylketene O-aryl S-alkyl acetals 6a-i is described. The compounds 2a-n are obtained by base-catalyzed alkylation of the respective β-oxo thiono esters 4a-n prepared by alkoxythiocarbonylation of active methylene ketones in the presence of sodium tert-butoxide. The corresponding O-dodecanyl 2o, O-benzyl 2p and O-aryl, S-methyl 6a-i acetals are synthesized via base-catalyzed displacement of the sulfonium salts 5a-b with the corresponding alkanol or phenol.
Highly efficient and selective displacement of alkylthio group on acylketene O,S-acetals by organocopper reagents: A novel route to 2-alkoxy/aryloxy-1-alkenylketones
作者:Barun K. Mehta、Sanchita Dhar、H. Ila、H. Junjappa
DOI:10.1016/0040-4039(95)01990-y
日期:1995.12
Acylketene O,S-acetals 1a-k undergo efficient and selective conjugate displacement of alkylthio group with organocopper(l) reagents to afford the corresponding 6-alkoxy/aryloxy enones 2-21 in good yields.