874-27-1Relevant articles and documents
Chemoselective Reduction of Sterically Demanding N,N-Diisopropylamides to Aldehydes
Xiao, Peihong,Tang, Zhixing,Wang, Kai,Chen, Hua,Guo, Qianyou,Chu, Yang,Gao, Lu,Song, Zhenlei
, p. 1687 - 1700 (2018/02/23)
A sequential one-pot process for chemoselectively reducing sterically demanding N,N-diisopropylamides to aldehydes has been developed. In this reaction, amides are activated with EtOTf to form imidates, which are reduced with LiAlH(OR)3 [R = t-Bu, Et] to give aldehydes by hydrolysis of the resulting hemiaminals. The non-nucleophilic base 2,6-DTBMP remarkably improves reaction efficiency. The combination of EtOTf/2,6-DTBMP and LiAlH(O-t-Bu)3 was found to be optimal for reducing alkyl, alkenyl, alkynyl, and 2-monosubstituted aryl N,N-diisopropylamides. In contrast, EtOTf and LiAlH(OEt)3 in the absence of base were found to be optimal for reducing extremely sterically demanding 2,6-disubstituted N,N-diisopropylbenzamides. The reaction tolerates various reducible functional groups, including aldehyde and ketone. 1H NMR studies confirmed the formation of imidates stable in water. The synthetic usefulness of this methodology was demonstrated with N,N-diisopropylamide-directed ortho-metalation and C-H bond activation.
Functionalization of 3-chlorobenzaldehyde
Aksjonova, Kristine,Belyakov, Sergey,Liepinsh, Edvards,Boman, Arne,Lundstedt, Torbjorn,Lek, Per,Trapencieris, Peteris
, p. 2200 - 2208 (2012/09/22)
2-Substituted 3-chlorobenzaldehydes were prepared from the corresponding 2-(3-chlorophenyl)-1,3-dioxolanes using an ortho-lithiation strategy. The 6-chloro-2-formylbenzamide exists only in a ring form, but 6-chloro-2- formylbenzoic acid esters were isolated in both forms as open chain and cyclic tautomers. 7-Chloro-3-hydroxy-3H-isobenzofuran-1-one reacted with nucleophilic reagents at the carbonyl or quaternary carbon depending on the character of nucleophile. Georg Thieme Verlag Stuttgart New York.
Ortho Metalation Directed by α-Amino Alkoxides
Comins, Daniel L.,Brown, Jack D.
, p. 1078 - 1083 (2007/10/02)
The addition of aromatic aldehydes to certain lithium dialkylamides in benzene or tetrahydrofuran gave α-amino alkoxides which were ortho lithiated with excess n-butyllithium.Subsequent alkylation and hydrolysis provided ortho-substituted aromatic aldehydes via a one-pot reaction.The ortho metalation of α-amino alkoxides derived from 1- and 2-naphthaldehyde and various substituted benzaldehydes was examined.When N,N,N'-trimethylethylenediamine was used as the amine component of the α-amino alkoxide, metalation could be carried out at lower temperatures.This rate increase is due to an intramolecular TMEDA-like assisted metalation.The synthetic utility of this ortho metalation, including how varying the amine component of the α-amino alkoxide affects the regiochemistry and metalation rate, is discussed.
