Synthesis of Phenolic Compounds by Trapping Arynes with a Hydroxy Surrogate
作者:Rajdip Karmakar、Sourav Ghorai、Yuanzhi Xia、Daesung Lee
DOI:10.3390/molecules200915862
日期:——
Trapping of arynes with various nucleophiles provides a range of heteroatom-functionalized arene derivatives, but the corresponding reaction with water does not provide phenol derivatives. Silver trifluroacetate (AgO2CCF3) can nicely solve this problem. It was found that in typical organic solvent, AgO2CCF3 readily reacts with arynes to generate trifluoroacetoxy organosilver arene intermediate, which, upon treating with silica gel, provides phenolic products. This protocol can be extended to the synthesis of α-halofunctionalized phenol derivatives by simply adding NBS (N-bromosuccinimides) or NIS (N-iodosuccinimides) to the reaction along with silver trifluroacetate, which provided α-bromo or α-iodophenol derivatives in good yield. However, the similar reactions with NCS (N-chlorosuccinimides) afforded only the protonated product instead of the expected α-chlorophenols derivatives. Interestingly, substrates containing silyl substituents on 1,3-diynes resulted in α-halotrifluoroacetates rather than their hydrolyzed product. Additionally, trapping the same arynes with other oxygen-based nucleophiles containing silver counter cation, along with NXS (N-halosuccinimides), generated α-halooxyfunctionalized products.
An efficient method for the construction of fused yne-substituted arylhalides by reaction of unactivated linear tetraynes with allyl halides via domino C-C coupling and formation of C-X bonds in the presence of Pd(OAc)2/PPh3 was developed.
A cascade hexadehydro-Diels–Alder (HDDA)/[3 + 2] cycloaddition reaction between tetrayne and N,N′-cyclic acylhydrazone is described. This strategy allows the efficient construction of fully substituted 2,3-dihydro-1H-indazole scaffolds which have insecticidal activity against the third instar larvae of Mythimna separata.