Nazarov Cyclization of 4-Cycloalkylidene-5-(trimethylsilyl)pent-1-en-3-one Derivatives. Synthesis of Spiro[4.5]decane, Spiro[4.4]nonane, and Their Derivatives
Spiro[4.5]decane and spiro[4.4]nonane ring systems were synthesized by FeCl3-induced Nazarov cyclization of α-(trimethylsilylmethyl)divinyl ketone derivatives. It was found that the double bond position of the product is controlled by the presence/absence of α′-substituent, while trimethylsilyl group is essential to obtain the products in good yields. Spiro[4.4]nonanes having exo-methylene group underwent
Amination of α,β-unsaturated (2-trimethylsilanylmethyl) carboxylic esters
作者:Tecla Gasperi、M Antonietta Loreto、Paolo A Tardella、Augusto Gambacorta
DOI:10.1016/s0040-4039(02)00390-8
日期:2002.4
The reactions of (2-trimethylsilanylmethyl) alpha,beta-unsaturated carboxylic ethyl esters with NsONHCO(2)Et and CaO produce, after treatment with AcOH, alpha-methylene N-(ethoxycarbonyl) beta-amino carboxylic esters through ring opening and elimination of the trimethylsilyl group from the intermediate aziridine. By ozonization and subsequent reductive cleavage these products give the corresponding N-(ethoxycarbonyl) beta-amino alpha-hydroxy esters. (C) 2002 Elsevier Science Ltd. All rights reserved.