Synthesis of 3,5-diacyl-4-phenyl-1,4-dihydropyridines
作者:M.-Lluïsa Bennasar、Cecília Juan、Joan Bosch
DOI:10.1016/s0040-4039(98)02084-x
日期:1998.12
via a regio- and chemoselective addition of Ph2Cu(CN)Li2 to β-substituted N-alkylpyridinium salts, followed by acylation of the intermediate 1,4-dihydropyridines with trichloroacetic anhydride and subsequent haloform-type reaction. A similar sequence using an N-silylpyridinium salt and PhMgBr allows the preparation of the corresponding N-unsubstituted dihydropyridines.
Intermolecular hetero Diels-Alder reactions of the enantiopure sulfinimine 11 with the enol ethers 12-16 at 20 °C and 11 kbar lead to the tetrahydropyridines 18-22 in high yield, with very good to good endo/exo selectivities, and with an induced diastereoselectivity of up to 2.1:1. The sulfinyl group in the adducts can be removed with MeLi followed by treatment with acetyl chloride or dimethyl sulfate
对映体纯亚磺亚胺 11 与烯醇醚 12-16 在 20 °C 和 11 kbar 下的分子间杂 Diels-Alder 反应导致高产率的四氢吡啶 18-22,具有非常好的内/外选择性,并具有诱导高达 2.1:1 的非对映选择性。加合物中的亚磺酰基可以用 MeLi 去除,然后用乙酰氯或硫酸二甲酯处理。根据该程序,21得到N-乙酰基四氢吡啶29或N-甲基二氢吡啶32。26的分子内Diels-Alder反应产生27,其分别转化为33和34。