reaction of aldehydes 3a–e with nitroalkanes and NH4OAc at reflux, reduction of the resulting nitroalkenes 4a–h with LAH at rt followed by protection with K2CO3 and PhSO2Cl at rt, one-pot oxidative cleavage annulation of olefins 5a–h with the one-pot combination of OsO4/NaIO4 at reflux, and hydrogenation of the corresponding enamines 6a–f. Aldehydes 3a–e was prepared from 2a and 2b in moderate yield of
A facile synthetic route toward diversified benzo[g]chrysenes 2 starting with commercially available isovanillin (1a) or 3-hydroxybenzaldehyde (1b) in modest total yields is described via the transformations of Claisen rearrangement of 3, Grignard addition of 4, DBU-promoted cyclodehydration of 5, and photolytic Scholl oxidative annulation of 6. Skeleton 3 is prepared via O-allylation of 1 with trans-cinnamyl
通过Claisen重排3,Grignard加成4,DBU促进的转化描述了一种以适中的总收率从商用异香兰素(1a)或3-羟基苯甲醛(1b)开始的向多样化苯并[ g ] chrysenes 2合成的简便途径。5的环脱水和6的光解Scholl氧化环化。骨架3是通过1与反式肉桂基溴的O-烯丙基化制备的。
<i>m</i>CPBA-Mediated Intramolecular Oxidative Annulation of <i>ortho</i>-Crotyl or Cinnamyl Arylaldehydes: Synthesis of Benzofused Five-, Six-, and Seven-Membered Oxacycles
作者:Meng-Yang Chang、Yu-Ting Hsiao、Kai-Hsiang Lai
DOI:10.1021/acs.joc.8b02146
日期:2018.11.16
mCPBA-mediated intramolecular oxidative annulation of ortho-crotyl or cinnamyl arylaldehydes provides chroman, coumaran, isochroman, and tetrahydrobenzo[c]oxepine under different reaction conditions. This research investigates the reaction conditions for facile and efficient transformation.
米CPBA介导的分子内氧化性环邻-crotyl或肉桂芳醛提供色满,香豆,异苯并二氢吡喃,四氢苯并和[ C ^ ]不同的反应条件下氧杂七环。这项研究调查了简便高效转化的反应条件。