18385-89-2Relevant academic research and scientific papers
Synthesis of 2 h-chromenes via hydrazine-catalyzed ring-closing carbonyl-olefin metathesis
Jermaks, Janis,Lambert, Tristan H.,Macmillan, Samantha N.,Zhang, Yunfei
, p. 9259 - 9264 (2019/10/08)
The catalytic ring-closing carbonyl-olefin metathesis (RCCOM) of O-Allyl salicylaldehydes to form 2H-chromenes is described. The method utilizes a [2.2.1]-bicyclic hydrazine catalyst and operates via a [3 + 2]/retro-[3 + 2] metathesis manifold. The nature of the allyl substitution pattern was found to be crucial, with sterically demanding groups such as adamantylidene or diethylidene offering optimal outcomes. A survey of substrate scope is shown along with a discussion of mechanism supported by DFT calculations. Steric pressure arising from syn-pentane minimization of the diethylidene moiety is proposed to facilitate cycloreversion.
An efficient preparation of 7-methoxychromanone
Cao, Zhisong,Liehr, Joachim G.
, p. 1233 - 1245 (2007/10/03)
The reaction of m-methoxyphenyl 7 with 3-chloropropionaldehyde diethyl acetal 8 and the subsequent treatments gave the corresponding 7-methoxychromanone 6 in overall 54% yield. This method represents an efficient preparation of chromanone.
Cesium Fluoride-Mediated Claisen Rearrangements of Phenyl Propargyl Ethers: Effect of a Substituent on the Phenyl Ring on the Rearrangement
Ishikawa, Tsutomu,Nagai, Keiko,Ohkubo, Naoko,Ishii, Hisashi
, p. 371 - 380 (2007/10/02)
Methoxy or methoxycarbonyl-substituted phenyl propargyl ethers were subjected to Claisen rearrangement either in the absence or in the presence of CsF.Substituent effect on the cyclization is discussed.
