Hetero-Diels–Alder reactions of α-carbonylated styrylphosphonates with enol ethers. High-pressure influence on reactivity and diastereoselectivity
Hetero-Diels–Alder reactions of α-carbonylated styrylphosphonates with enol ethers. High-pressure influence on reactivity and diastereoselectivity
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α-羰基化苯乙烯基膦酸酯与烯醇醚的杂狄尔斯-阿尔德反应高压对反应性和非对映选择性的影响。
DOI：
10.1039/a903972d
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
N. Collignon*
中科院分区：
文献类型：
--
作者：
H. Al;J. Maddaluno;S. Masson*;N. Collignon*
通过Knoevenagel型合成法，合成了不同取代的α-羰基苯乙烯基膦酸酯5，并将其作为恶二烯与烯醇醚进行杂Diels-桤木[4 + 2]环加成反应，得到了新的膦酰基化3，4-二氢-2H-吡喃6。据证实，反应的反应性，以及反式-非对映选择性的反应，是显着增强通过使用高压条件下，特别是在存在的ButOH作为共溶剂。此外，通过串联Knoevenagel和异Diels-桤木反应实现了6的一锅合成。
Variously substituted α-carbonylated styrylphosphonates 5 were easily prepared by Knoevenagel-type syntheses, and used as oxadienes in hetero-Diels–Alder [4 + 2] cycloadditions with enol ethers, to give new phosphonylated 3,4-dihydro-2H-pyrans 6. It was confirmed that the reactivity , as well as the trans-diastereoselectivity of the reaction, was significantly enhanced by the use of high-pressure conditions, particularly in the presence of ButOH as a co-solvent. Moreover, a one-pot synthesis of 6 via a tandem-sequence Knoevenagel and hetero-Diels–Alder reactions was achieved.