Rh(II)-Catalyzed Denitrogenative Transannulation of <i>N</i>-Sulfonyl-1,2,3-triazolyl Cyclohexadienones for the Synthesis of Benzofurans and Cyclopropa[<i>cd</i>]indole-carbaldehydes
作者:Geetanjali S. Sontakke、Kuntal Pal、Chandra M. R. Volla
DOI:10.1021/acs.joc.9b01924
日期:2019.9.20
A rhodium-catalyzed intramolecular denitrogenative transannulation of N-sulfonyl-1,2,3-triazole-tethered cyclohexadienones has been achieved for the synthesis of benzofurans and cyclopropa[cd]indole-carbaldehydes in an operationally simple procedure. Remarkably, the reaction pathway is fully dependent on the linker heteroatom (O or N) present between the cyclohexadienone unit and triazole moiety. In
N-磺酰基-1,2,3-三唑系链的环己二酮的铑催化的分子内脱氮环转移反应已经可以在操作简单的过程中合成苯并呋喃和环丙烷[ cd ]吲哚-甲醛。明显地,反应途径完全取决于存在于环己二酮单元和三唑部分之间的接头杂原子(O或N)。在O-连接的三唑的情况下,发生由分子内环丙烷化和重排组成的级联序列,导致形成苯并呋喃,而在N-连接的三唑的情况下,仅分离出环丙烷[ cd ]吲哚-甲醛。
Metal-free visible-light induced cyclization/substitution cascade reaction of alkyne-tethered cyclohexadienones and diselenides: access to 5-hydroxy-3-selenyl-4a,8a-dihydro-2<i>H</i>-chromen-6(5<i>H</i>)-ones
A simple and efficient Se-radical triggered cyclization/substitution cascadereaction of alkyne-tethered cyclohexadienones to afford 5-hydroxy-3-selenyl-4a,8a-dihydro-2H-chromen-6(5H)-ones has been developed. This transformation via the 3,5-diselenyl-4a,8a-dihydro-2H-chromen-6(5H)-one intermediate followed by hydrolysis in the presence of CsOAc affords the desired product 3. The resulting products
Sulfonylative and Azidosulfonylative Cyclizations by Visible-Light-Photosensitization of Sulfonyl Azides in THF
作者:Shaoqun Zhu、Atchutarao Pathigoolla、Grace Lowe、Darren A. Walsh、Mick Cooper、William Lewis、Hon Wai Lam
DOI:10.1002/chem.201704380
日期:2017.12.11
generation of sulfonyl radicals from sulfonyl azides using visible light and a photoactive iridium complex in THF is described. This process was used to promote sulfonylative and azidosulfonylative cyclizations of enynes to give several classes of highly functionalized heterocycles. The use of THF as the solvent is critical for successful reactions. The proposed mechanism of radical initiation involves
Enantioselective Rh-Catalyzed Domino Transformations of Alkynylcyclohexadienones with Organoboron Reagents
作者:Juliane Keilitz、Stephen G. Newman、Mark Lautens
DOI:10.1021/ol400363f
日期:2013.3.1
A new enantioselective rhodium-catalyzed domino reaction is described that gives access to fused heterocycles by desymmetrization of alkyne-tethered cyclohexadienones. Two new C–C bonds and two stereocenters are formed in one step with good enantioselectivity. In contrast to prior reports, it was found that a vinylidene is not involved in the product formation but that syn-addition of the rhodium-aryl
Catalytic, Regioselective Hydrocarbofunctionalization of Unactivated Alkenes Triggered by <i>trans</i>-Acetoxypalladation of Alkynes
作者:Rahul K. Shukla、Atul K. Chaturvedi、Subir Pal、Chandra M. R. Volla
DOI:10.1021/acs.orglett.1c00118
日期:2021.2.19
Herein we demonstrate a Pd(II)-catalyzed regioselective hydrocarbofunctionalization of unactivatedalkenes. The σ-vinyl-palladium(II) intermediate generated by the trans-acetoxypalladation of alkynes was added across carbon–carbon double bond to realize an efficient hydroalkenylation protocol. Bidentate auxiliary 8-aminoquinoline controls the regioselectivity of the carbopalladation step and thereby