Reaction of ethoxycarbonylcarbene with n-hexadecane and n-docosane
作者:A. D. Forbes、J. Wood
DOI:10.1039/j29710000646
日期:——
A novel variation in reactivity of the carbene towards the secondary positions of an n-alkane has been observed. In the photolyses, the relative rate of insertion of ethoxycarbonylcarbene for secondary C–H:primary C–H was found to be 2·1 at position 2, steadily falling to ca. 1·4 at the secondary positions in the middle of the chain. Similar trends were noted in thermal reactions. Other products of
热和光解生成的乙氧基羰基碳烯与高分子量正构烷烃(> C 10)的反应产生了预期的C–H键插入产物,例如在正十六烷的情况下,异构体C 18酸的乙酯。热生成的物质产生的产率高得多,基于卡宾前体重氮乙酸乙酯计算,产率最高可达75%;讨论了可能的解释。已经观察到卡宾对正构烷烃的仲位置的反应性的新变化。在光解过程中,发现乙氧基羰基碳烯相对于次要C–H的相对插入速率:主C–H在位置2处为2·1,稳定地下降到大约1。在链中间的次要位置为1·4。在热反应中也发现了类似的趋势。描述了反应的其他产物。
Polyoxometalates: Powerful Catalysts for Atom-Efficient Cyclopropanations
The polyoxometalate-based catalytic cyclopropanation of olefins by ethyl diazoacetate (EDA) is reported. The outstanding catalyst productivity (TONs up to 100,000) and the use of equimolar EDA/olefin ratio confer to the methodology a high sustainability. Preliminary mechanistic investigations are also discussed.
Ethylene can be directly converted into ethyl 1-cyclopropylcarboxylate upon reaction with ethyl diazoacetate (N2CHCO2Et, EDA) in the presence of catalytic amounts of IPrAuCl/NaBArF 4 (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazole-2-ylidene; BArF 4 = tetrakis(3,5-bis(trifluoromethyl)phenyl)borate).
Large-Scale Tandem Cyclization Applied to Potentially High-Volume SSTR4 Agonists
作者:Louise M. Guard、John R. Rizzo
DOI:10.1021/acs.oprd.4c00144
日期:2024.7.19
Somatostatin receptor subtype 4 (SSTR4) antagonists are potential clinical targets for pain. We describe the efforts toward a robust large-scalesynthesis of certain small-molecule SSTR4 agonist compounds. Previous routes used metal-mediated reactions and produced stereochemical mixtures. The molecule has a 3-azabicyclo[3.1.0]hexane ring system with cis-stereochemistry. A unique tandem cyclization