1型四氢吡啶并[4,3 - e ] -1,4,2-二恶嗪的特殊性质使得可以通过常规还原剂在区域和立体选择性地获得取代的N-氨基甲酰基四氢吡啶。通过使用三乙基硼氢化锂通过空前的级联顺式-S N 2'还原/氨基甲酸酯还原/环化反应,可以生产出一种全新的,具有生物活性的双环1,3-二氮杂-4-氧杂-[3.3.1]-壬烯骨架。反应。借助于计算研究已经合理化了烯丙基还原过程中显着的区域选择性开关。
On the regioselectivity of the reaction of N-methoxycarbonylpyridinium chloride with Grignard reagents: highly regioselective synthesis of 2-substituted N-methoxycarbonyl-1,2-dihydropyridines.
Whereas alkyl Grignardreagents undergo 1,2- and 1,4-additions to N-methoxycarbonylpyridinium chloride in a variable ratio, alkenyl and alkynyl Grignardreagents do the exclusive 1,2-addition to afford 2-substituted N-methoxycarbonyl-1,2-dihydropyridines in fair to excellent yields.
Highly Regioselective α-Addition of Alkynyl and Alkenyl Grignard Reagents to 1-Alkoxycarbonylpyridinium Salts and Its Application to Synthesis of 1-Azabicycloalkanes and (±)-Solenopsin A
Nucleophilic addition of a variety of alkynyl and alkenyl Grignardreagents to 1-methoxycarbonylpyridinium chloride takes place at the α-position in a highly regioselective manner to give 2-substituted 1-methoxycarbonyl-1,2-dihydropyridines exclusively, while, with alkyl Grignardreagents, a lack of the regioselectivity is observed. These results may be explained by the HSAB principle. The high α-regioselectivity
reducing agents. A completely novel, biologically active, bicyclic 1,3-diaza-4-oxa-[3.3.1]-nonene scaffold can be generated by the use of lithium triethylborohydride through unprecedented cascade syn-SN2′ reduction/carbamate reduction/cyclization reactions. The remarkable regioselectivity switches in the allylic reduction process have been rationalized with the aid of computational studies.
1型四氢吡啶并[4,3 - e ] -1,4,2-二恶嗪的特殊性质使得可以通过常规还原剂在区域和立体选择性地获得取代的N-氨基甲酰基四氢吡啶。通过使用三乙基硼氢化锂通过空前的级联顺式-S N 2'还原/氨基甲酸酯还原/环化反应,可以生产出一种全新的,具有生物活性的双环1,3-二氮杂-4-氧杂-[3.3.1]-壬烯骨架。反应。借助于计算研究已经合理化了烯丙基还原过程中显着的区域选择性开关。
Photochemical generation of the 2-azabicyclo[4.2.0]octa-4,7-diene skeleton
作者:Tyler Fahrenhorst-Jones、G. Paul Savage、Craig M. Williams
DOI:10.1071/ch22139
日期:——
A 2-azabicyclo[4.2.0]octa-4,7-diene derivative was unexpectedly isolated from the photochemical irradiation of 2-vinyl-1,2-dihydropyridine. A cascading 6π–8π–4π electrocyclic rearrangement has been proposed as a possible mechanistic pathway.