Controlled α-mono- and α,α-di-halogenation of alkyl sulfones using reagent–solvent halogen bonding
作者:Christopher M. Poteat、Vincent N. G. Lindsay
DOI:10.1039/c9cc00550a
日期:——
The direct and selective α-mono-bromination of alkylsulfones was achieved through base-mediated electrophilic halogenation. The appropriate combination of solvent and electrophilic bromine source was found to be critical to control the nature of the products formed, where reagent–solvent halogen bonding is proposed to control the selectivity via alteration of the effective size of the electrophilic
Specific ortho orientation in the vicarious substitution of hydrogen in aromatic nitro compounds with carbanion of chloromethyl phenyl sulfone
作者:M. Makosza、T. Glinka、A. Kinowski
DOI:10.1016/s0040-4020(01)91141-x
日期:1984.1
Vicariousnucleophilic substitution of hydrogen atoms in nitroarenes with chloromethylphenyl sulfone proceeds selectively ortho to the nitro group when carried out in t-BuOK/THF base/solvent system. In the majority of 3-substituted nitrobenzene derivatives substitution occurs at the most hindered position 2. These conditions offer an efficient method of synthesis of 2,6 and 2,3-disubstituted nitrobenzene
photoexcitation of enamines to trigger the formation of reactive carbon-centered radicals from iodosulfones, while the ground-state chiral enamines provide effective stereochemicalcontrol over the radical trapping process. The phenylsulfonyl moiety, acting as a redox auxiliary group, facilitates the generation of radicals. In addition, it can eventually be removed under mild reducing conditions to reveal methyl
Methyl Radical Initiated Kharasch and Related Reactions
作者:Nicholas D. C. Tappin、Philippe Renaud
DOI:10.1002/adsc.202001000
日期:2021.1.5
chalcogen group transfer radical additions is reported. The procedure relies on the thermal decomposition of di‐tert‐butylhyponitrite (DTBHN), a safer alternative to the explosive diacetyl peroxide, to produce highly reactive methylradicals that can initiate the chain process. This mode of initiation generates byproducts that are either gaseous (N2) or volatile (acetone and methyl halide) thereby facilitating
Radical alkylations of activated alkyl iodides and bromides were achieved usingvinyltriflates in the presence of hexadimethyltin, whereas those of unactivated C-H bonds usingvinyltriflates proceeded cleanly under tin-free conditions.