Tosylhydrazine mediated conjugate reduction and sequential reductive coupling cyclization: synthesis of 2-arylchromans
摘要:
Tosylhydrazine mediated conjugate reduction of 2-hydroxyl chalcones and sequential reductive coupling cyclization is described. This is an unprecedented protocol and an extremely efficient method for a one-pot domino synthesis of 2-arylchromans in good to excellent yields from commercially available, cheap starting materials. More importantly, the two-step reactions can be easily controlled to afford dihydrochalcones or 2-arylchromans by the mole amounts of tosylhydrazine. Furthermore, the operational simplicity of the process and the high functional group tolerance are remarkable. (C) 2015 Elsevier Ltd. All rights reserved.
Rh-Catalyzed Decarbonylative Addition of Salicylaldehydes with Vinyl Ketones: Synthesis of Taccabulins A-E
作者:Maddali L. N. Rao、Boddu S. Ramakrishna
DOI:10.1002/ejoc.201901314
日期:2019.12.15
A Rh‐catalyzed decarbonylative addition of salicylaldehydes with vinylketones was developed for the synthesis of o‐hydroxydihydrochalcones in good yields. This protocol was applied in the synthesis of taccabulin family of natural products.
Brønsted Acid Catalyzed Intramolecular Allylic Substitution Reaction of Allylic Alcohols: A Facile Synthesis of 2-Vinylchromans
作者:Chang-Hua Ding、Bin Xu、Yun-Fan Li、Yu-Ting Xi、Kai-Ji Hu、Qitao Tan
DOI:10.1055/a-2301-9223
日期:2024.11
Brønsted acidcatalyzedintramolecular allylic substitution reaction of secondary and tertiary allylic alcohols has been developed. A variety of 2-vinylchromans were efficiently prepared in moderate to excellent yields. The given method features wide substrate scope, operational simplicity, and mild, metal-free reaction conditions. The practicability of the method was demonstrated by a gram-scale reaction
An unexpected rearrangement-hydration reaction sequence of 2H-chromenes to dihydrochalcones under catalysis of HAuCl4
作者:Gourhari Maiti、Utpal Kayal、Rajiv Karmakar、Rudraksha N. Bhattacharya
DOI:10.1016/j.tetlet.2012.08.117
日期:2012.11
2-Aryl-2H-chromenes in aqueous DCM medium under catalysis of HAuCl4 are converted into 3-(2-hydroxyaryl)-1-arylpropan-1-ones through hydration-rearrangement reaction sequence in very good yield. The key step probably involves the [1,5] hydride shift followed by the hydrolysis under the reaction condition. The notable advantages of this method are operational simplicity and ease of isolation of products and also provide a pathway to convert the chalcone into DHCs with the transposition of carbonyl group. (C) 2012 Elsevier Ltd. All rights reserved.