THE TRANSIENT DIENOPHILE DIETHYL THIOXOMALONATE AND ITS S-OXIDE (SULFINE) FORMED BY RETRO-DIELS-ALDER CLEAVAGE REACTIONS

被引:28
作者
KIRBY, GW
MCGREGOR, WM
机构
[1] Department of Chemistry, University of Glasgow
来源
JOURNAL OF THE CHEMICAL SOCIETY-PERKIN TRANSACTIONS 1 | 1990年 / 11期
关键词
D O I
10.1039/p19900003175
中图分类号
O62 [有机化学];
学科分类号
070303 ; 081704 ;
摘要
Diels-Alder adducts 3 and 4 of diethyl thioxomalonate 1, formed from diethyl oxomalonate (mesoxalate) and phosphorus pentasulphide, with cyclopentadiene and anthracene, dissociate at 111°C to release the reactive thioketone 1. This was trapped in situ with 2,3-dimethylbuta1,3-diene to give the corresponding cycloadduct 2. Similarly, the thioketone 1 reacted with 2-trimethylsiloxybuta-1,3-diene 8 to form only the 5-trimethylsiloxythiine13, and with β-pinene16 to form only one 'ene' product 17b, with C-S bond formation. The S-oxide 19 of the anthracene adduct 4 and the exo-S-oxide 27 of the cyclopentadiene adduct 3 likewise dissociated thermally to release the corresponding sulphine, diethyl thioxomalonate S-oxide 21, which was trapped in situ as the dimethylbutadiene adduct 23. The exo-sulphoxide 27, when heated alone, gave the sultene 29, presumably via [2,3]-sigmatropic rearrangement of the transient endo-sulphoxide 28. The sulphine 21, generated by flash vacuum pyrolysis of the anthracene adduct 19, reacted at low temperature with cyclopentadiene to give the exo-sulphoxide 27, and with water to give diethyl malonate.
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页码:3175 / 3181
页数:7
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