TMSOTf-Promoted Addition of Alkynes to Aldehydes: A Novel Synthesis of Chroman-4-ones
作者:Ji Yeon Park、Punna Reddy Ullapu、Hyunah Choo、Jae Kyun Lee、Sun-Joon Min、Ae Nim Pae、Youseung Kim、Du-Jong Baek、Yong Seo Cho
DOI:10.1002/ejoc.200800782
日期:2008.11
A novel synthetic method to prepare chalcones 2 and chroman-4-ones 3 by TMSOTf-promotedaddition of alkynes 1 to various aldehydes has been developed. The ratios of chalcones 2, chroman-4-ones 3 and hydrated products 4 varied depending upon the substituents R (nBu, phenyl, H and TMS) on the alkynes 1. We also describe the transformation of the chalcones 2 to the corresponding chroman-4-ones 3 under
Tandem Alkyne Hydroacylation and Oxo-Michael Addition: Diastereoselective Synthesis of 2,3-Disubstituted Chroman-4-ones and Fluorinated Derivatives
作者:Xiang-Wei Du、Levi M. Stanley
DOI:10.1021/acs.orglett.5b01447
日期:2015.7.2
Tandem reactions involving Rh-catalyzed intermolecular hydroacylations of alkynes with salicylaldehydes followed by intramolecular oxo-Michael additions are described for the diastereoselective synthesis of 2,3-disubstituted chroman-4-ones. The tandem hydroacylation/oxo-Michael additions occur to form 2,3-disubstituted chroman-4-ones in high yields from a range of 1,2-disubstituted acetylenes and substituted
2-Hydroxybenzaldehydes smoothly and efficiently react with various internal and terminal alkynes accompanied by cleavage of the aldehyde C–H bond by using a rhodium-based catalyst system of [RhCl(cod)]2/dppf/Na2CO3 [cod = 1,5-cyclooctadiene; dppf = 1,1′-bis(diphenylphosphino)ferrocene] to give the corresponding 2-alkenoylphenols in good to excellent yields. The regioselectivity of the reaction depends on the substituents of acetylene; an oxygen function on the propargylic position shows a considerable directing effect. The aldehydes can also react with some alkenes or allenes, such as triethylvinylsilane and 2-norbornene or 3-methyl-1,2-butadiene and 1,2-nonadienes, in place of alkynes.