Dehydrative Fragmentation of 5-Hydroxyalkyl-1<i>H</i>-tetrazoles: A Mild Route to Alkylidenecarbenes
作者:Duncan J. Wardrop、John P. Komenda
DOI:10.1021/ol300276p
日期:2012.3.16
The development of a mild, base-free method for the generation of alkylidenecarbenes is reported. Treatment of 5-hydroxyalkyl-1H-tetrazoles with carbodiimides generates products arising from the 1,2-rearrangement or [1,5]-C–H bond insertion of a putative alkylidenecarbene. Formation of this divalent intermediate is proposed to occur by way of a tetraazafulvene, which undergoes extrusion of 2 mol of
Synthesis of five-membered unsaturated compounds from ketones via cyanophosphates under neutral conditions: [1,5]-C H insertion of alkylidene carbenes generated by tetrazole fragmentation
Cyanophosphates (CPs) can easily be prepared via the reactions of carbonyl compounds with diethyl phosphorocyanidate (DEPC) in the presence of LiCN (cat.) under non-aqueous conditions. Treatment of ketone-derived CPs with TMSN3/Bu2SnO (cat.) in toluene at reflux produces cyclopentenes or heterocyclic products in good yields under neutral conditions. In this two-step transformation, CPs may form tetrazolylphosphates
在非水条件下,在LiCN(cat。)存在下,羰基化合物与磷腈二乙酯(DEPC)的反应可轻松制得氰基磷酸盐(CPs)。在中性条件下,用甲苯中的TMSN 3 / Bu 2 SnO(cat。)在甲苯中处理酮衍生的CP,可以高产率生产环戊烯或杂环产物。在此两步转化过程中,CP可能形成四唑基磷酸酯,随后对其进行连续裂解以生成亚烷基卡宾,这些卡宾经过[1,5] -CH插入可生成五元化合物。