15963-07-2Relevant articles and documents
Neighboring Carbonyl Group Assisted Oxyacetoxylation of Propargylic Carboxylates with Retention of Chirality under Metal Free Condition
Pradhan, Tapas R.,Mohapatra, Debendra K.
, p. 3605 - 3611 (2019/07/04)
A metal-free oxyacetoxylation method of primary, secondary and tertiary propargylic carboxylates with retention of chirality was presented. The reaction proceeds through the intramolecular nucleophilic attack of the neighboring carbonyl group on an alkynyliodonium intermediate. The process is general with broad substrate scope and is amenable for application to a variety of propargyl carboxylates including those obtained from natural products. Insight into the mechanistic pathway by isotopic labelling (using H2O18 and D2O) and controlled experiments confirmed. (Figure presented.).
Synthesis of Multisubstituted Allenes, Furans, and Pyrroles via Tandem Palladium-Catalyzed Substitution and Cycloisomerization
Ryu, Taekyu,Eom, Dahan,Shin, Seohyun,Son, Jeong-Yu,Lee, Phil Ho
supporting information, p. 452 - 455 (2017/02/10)
A palladium-catalyzed propargyl substitution reaction of propargyl acetates with indium organothiolates is developed for the synthesis of multisubstituted allenyl sulfides. This procedure can be applied to the synthesis of multisubstituted furans and pyrroles via tandem palladium-catalyzed propargyl substitution and cycloisomerization reaction in one pot.
Complementary iron(II)-catalyzed oxidative transformations of allenes with different oxidants
Sabbasani, Venkata R.,Lee, Hyunjin,Xia, Yuanzhi,Lee, Daesung
, p. 1151 - 1155 (2016/01/20)
Substituent- and oxidant-dependent transformations of allenes are described. Given the profound influence of the substituent on the reactivity of allenes, the subtle differences in allene structures are manifested in the formation of diverse products when reacted with different electrophiles/oxidants. In general, reactions of nonsilylated allenes involve an allylic cation intermediate by forming a C-O bond, at the sp-hybridized C2, with either DDQ (2,3-dichloro-5,6-dicyano-p-benzoquinone) or TBHP (tert-butyl hydroperoxide), along with FeCl2·4 H2O (10 mol %). In contrast, silylated allenes favor the formation of propargylic cation intermediates by transferring the allenic hydride to the oxidant, thus generating 1,3-enynes (E1 product) or propargylic THBP ethers (SN1 product). The formation of these different putative cationic intermediates from nonsilylated and silylated allenes is strongly supported by DFT calculations. Profound impact: Iron(II)-catalyzed transformations of allenes induced by either DDQ or tBuOOH depend on the substituent on the allenes. Nonsilylated and silylated allenes show complementary reactivity upon exposure to DDQ and tBuOOH in the presence of an iron(II) catalyst. Nonsilylated allenes incorporate the oxidant at the sp-hybridized carbon, whereas the silylated allenes generate 1,4-dehydrogenated 1,3-enynes. DDQ=2,3-dichloro-5,6-dicyano-1,4-benzoquinone.