Lewis acid-catalyzed conjugate addition-cyclization reactions of ethenetricarboxylates with substituted propargyl alcohols: stereoselectivity in the efficient one-pot synthesis of methylenetetrahydrofurans.
Oxygen-containing heterocyclic systems are important structures in organic chemistry because of their presence in many biologically active compounds. In this work, a Lewis acid-catalyzed cyclization of ethenetricarboxylate derivatives 1 with substituted propargyl alcohols to give methylenetetrahydrofurans was investigated. Reaction of 1 and gamma-silicon-substituted propargyl alcohols 4 with ZnBr2 at 80-110 degrees C led to (Z)-silicon-substituted products stereoselectively. Reaction of 1 and gamma-ester-substituted propargyl alcohol 7 in the presence of various Lewis acids gave ester-substituted methylenetetrahydrofurans stereoselectively. Interesting Lewis acid dependency on stereoselectivity for the reaction of 7 was found. Reaction of alpha-substituted propargyl alcohols also gave cyclized products.
Morikawa
Satoshi
S
Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan.
Yamazaki
Shoko
S
Tsukada
Momoko
M
Izuhara
Suguru
S
Morimoto
Tsumoru
T
Kakiuchi
Kiyomi
K
D000143:Acids / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D002264:Carboxylic Acids / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D005663:Furans / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D020005:Propanols / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D013055:Spectrophotometry, Infrared; D013237:Stereoisomerism
D000143:Acids; D000480:Alkynes; D002264:Carboxylic Acids; D005663:Furans; D020005:Propanols; C028255:propargyl alcohol