Herein we disclose
a metal-free, N/O-centered radical-promoted
Minisci reaction, in which the coupling of various heteroarenes with
simple alkanes proceeds under mild conditions. The reaction conditions
are neutral; no extra acid is added to preactivate N-heteroarenes
in the Minisci reaction. The N-/O-centered radicals are generated
directly from amide (TsNHMe) or alcohol (CF3CH2OH) under visible-light irradiation. This green and eco-friendly
synthetic process may find potential use in medicinal chemistry.
Diazophosphane HPN2, a
heavy analogue of hydrazoic
acid
(HN3), has been synthesized at low temperature (10 K) through
photolytic reactions of molecular nitrogen (N2) with phosphine
(PH3) and phosphaketene (HPCO) under irradiations at 193
and 365 nm, respectively. The characterization of HPN2 and
its isotopologues DPN2 and HP15N2 by matrix-isolation IR and UV–vis spectroscopy is supported
by quantum chemical calculations at the CCSD(T)-F12a/cc-pVTZ-F12 level
of theory. Upon irradiation at 266 nm, the P–N bond in HPN2 breaks, whereas its photolysis at 193 nm generates the elusive
phosphinyl radical •PN2.
A metal‐free deformylative Minisci‐type reaction is disclosed by using aliphatic aldehydes as alkyl radical precursors. The reaction proceeds via a sequence of hydrogen atom abstraction (HAA) from aldehyde and decarbonylation under mild photochemical conditions. The transformation offers many advantages including good regioselectivity, broad substrate scope, and easy operation. The reaction is also amenable to late‐stage functionalization of complex heteroarenes, and can be readily performed on gram scale.
Radical-mediated difunctionalization of alkenes through the remote functional group migration (FGM) process paves an ingenious avenue for simultaneous cleavage and reconstruction of C-C bonds. Recently, our group has systematically disclosed the strategy of remote FGM for radical-mediated difunctionalization of unactivated alkenes. A portfolio of functional groups including cyano, heteroaryl, alkynyl, oximino, and carbonyl showcase the migratory aptitude, leading to new C-C bonds under radical conditions. Meanwhile, a series of other chemical bonds such as C-C, C-N, C-P, C-Si, and C-S are readily constructed in the reaction. Considering the synthetic utility and flexible transformation of alkynes, the radical alkynylation of unactivated alkenes via remote alkynyl migration we firstly reported provides an efficient approach for the incorporation of alkynes and has received considerable attention. On the other hand, fluorine-and sulfonyl-containing molecules play vital roles in organic and medicinal chemistry owing to their important chemical and physical characters. Therefore, the concomitant introduction of an alkynyl and a trifluoromethyl/sulfonyl group into one molecule is of great synthetic value. Herein we report a useful method for carbo-trifluoroalkylation/sulfonylation of unactivated olefins. The addition of extrinsic radical to alkene triggers the intramolecular FGM via a five-membered transition state along with a cascade of bond fission and formation. The typical procedure is as follows: a mixture of propargyl alcohol 1, sulfonyl chloride, fac-Ir(ppy) 3 , and base is loaded in a flame-dried reaction vial which is subjected to evacuation/flushing with nitrogen three times. Solvent is added to the mixture via syringe and the mixture is then stirred at 25 ℃ until the starting material is consumed monitored by TLC. The mixture is concentrated, and purified by flash column chromatography on silica gel (eluent: petroleum ether/ethyl acetate) to give the product.
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