Ni-Catalyzed Formal Cross-Electrophile Coupling of Alcohols with Aryl Halides
作者:Quan Lin、Guobin Ma、Hegui Gong
DOI:10.1021/acscatal.1c04239
日期:2021.11.19
and TBAB as the mild bromination reagents enables rapid transformation of a wide range of alcohols to their bromide counterparts within one to 5 min in CH3CN and DMF, which is compatible with the Ni-catalyzed cross-electrophile coupling conditions in the presence of a chemical reductant. The present method is suitable for arylation of a myriad of structurally complex alcohols with no need for prepreparation
未活化醇的直接偶联仍然是当前合成化学中的一个挑战。我们在此展示了一种建立在醇与芳基卤化物的原位卤化/还原偶联以形成 Csp 2 -Csp 3键的策略。2-氯-3-乙基苯并[ d ]恶唑-3-鎓盐 (CEBO) 和 TBAB 作为温和溴化试剂的组合能够在 CH 3 中在一到 5 分钟内将范围广泛的醇快速转化为其溴化物对应物CN 和 DMF,在化学还原剂存在下与 Ni 催化的交叉亲电偶联条件相容。本方法适用于无数结构复杂的醇的芳基化,而无需制备卤代烷。更重要的是,温和且动力学快速的溴化过程在对称二醇的溴化/芳基化和多元醇中较少的空间位阻羟基中显示出良好的选择性,从而为二醇和多元醇的选择性官能化提供了希望,而无需费力的保护/脱保护操作。这项工作的实用性在许多碳水化合物、药物化合物和天然醇的芳基化中也很明显。
Rule of five cyclizations in 5-hexenyl radicals and photocycloadditions of 1,5-hexadienes: effect of 4-oxa substitution
作者:Albert R. Matlin、Karen Feit Brinton、Belinda Tsao Nivaggioli
DOI:10.1002/poc.1120
日期:2007.2
The effect of 4-oxa substitution on the regiochemistry and rate of 5-hexenyl radical cyclizations was investigated, as a potential model for [2 + 2] photocycloadditions of 2-acyl-4-oxa-1,5-hexadienes. Increasing the electron density in the alkene decreases the rate of cyclization in the 4-oxa-hexenyl radicals, relative to the all carbon analogs, but has little effect on the regioselectivity of the
The present invention relates to novel N-substituted azaheterocyclic compounds of the general formula
wherein X, Y, Z, A, R1, R2, r and s are as defined in the detailed part of the present description or salts thereof, to methods for their preparation, to compositions containing them, and to their use for the clinical treatment of painful, hyperalgesic and/or inflammatory conditions in which C-fibers play a pathophysiological role by eliciting neurogenic pain or inflammation as well as their use for treatment of indications caused by or related to secretion and circulation of insulin antagonising peptides.
3-Halogenoalkoxytributyltin compounds prepared from 1,3-halogenohydrins and tributyltin ethoxyde decompose at 200° leading to the corresponding oxetanes. This reaction is a very convenient method of preparation of this kind of heterocycles.
Synthesis of 9-substituted tetrahydrodiazepinopurines—asmarine A analogues
作者:Doron Pappo、Yoel Kashman
DOI:10.1016/s0040-4020(03)01058-5
日期:2003.8
unique tetrahydro[1,4]diazepino-[1,2,3-g,h]purine (THDAP) structure and interesting biological properties. Three synthetic approaches were employed for the preparation of the THDAP system. Several N-9, of the purine, protecting groups were investigated. 15N-Chemical shifts measured from 15NH HMBC experiments for several compounds, that demonstrate the influence of various structural features on the 15N-resonances