A Regioselective Lithiation of ortho-Cresols Using the Bis(dimethylamino)phosphoryl Group as a Directing Group: General Synthesis of 2,3-Dihydrobenzo(b)furans Including Naturally Occurring Neolignans.
摘要:
作为关键步骤,通过对原甲苯基四甲基磷二酰胺进行区域选择性石化作用,然后加入芳香醛,开发了一种 2-芳基-2,3-二氢苯并[b]呋喃的通用合成方法。生成的二硫代锂与芳香醛反应,得到 1,2-二硫代乙醇衍生物。用氢化铝锂还原去除磷基,然后进行酸处理,可得到 2-芳基-2,3-二氢苯并[b]呋喃,总产率很高。在以 O-双(二甲基氨基)磷酸化丁香酚或异丁香酚为起始物,对 (±)-licarin B 和 (±)-carnatol 等高度取代的新木犀草素天然产物进行区域选择性合成时,证明了这一策略的实用性。
Formation of alcohols from alkenes with TiCl<sub>4</sub>–NaBH<sub>4</sub>
作者:Shinzo Kano、Yasuyuki Tanaka、Satoshi Hibino
DOI:10.1039/c39800000414
日期:——
The reaction of alkenes with TiCl4âNaBH4 in 1,2-dimethoxyethane afforded alcohols, the hydroxy group of which was introduced in an anti-Markovnikov direction.
substituted trans 2,3‐diaryloxiranes were regio‐ and stereoselectively arylated by arylzinc reagents, obtained from the corresponding boronic acids by B–Zn exchange. The method allowed a direct and high yielding access to trans 2,3‐diphenyl 2,3‐dihydro benzofuran. The use of enantioenriched starting diaryl oxiranes resulted in no loss of stereochemical integrity in the final trans 2,3‐dihydrobenzofuran