Homolytic Base-Promoted Aromatic Alkylations by Alkyl Halides1
摘要:
Electron-transfer chain reactions leading to regioselective alkylations of benzenes bearing electron-withdrawing substituents can be observed with alkyl halides in the presence of the radical initiator (Bu3Sn)(2) and the proton acceptor 1,4-diazabicyclo[2.2.2]octane (DABCO). Yields vary from low to high depending on the benzene derivatives. The role of DABCO is to abstract a proton from the substituted cyclohexadienyl adduct radical to form a radical anion which then transfers an electron to RX and is converted to the alkylated product itself. The rate of this electron-transfer step is probably not fast enough to sustain a good radical chain reaction so that further generation of R-. from excess (Bu3Sn)(2) and RX is necessary.
Homolytic Base-Promoted Aromatic Alkylations by Alkylmercury Halides<sup>1</sup>
作者:Glen A. Russell、Ping Chen、Byeong Hyo Kim、Ragine Rajaratnam
DOI:10.1021/ja971809n
日期:1997.9.1
Electron transfer chain reactions leading to substitution in electronegatively substituted benzene derivatives can be observed with alkylmercury halides in the presence of proton acceptors such as ...