Abstract:N-Alkynylated sulfoximines have been obtained by copper-catalyzed cross-coupling reactions starting from NH-sulfoximines and bromoacetylenes in moderate to good yields. The reaction conditions are mild, and the substrate scope is wide.
“…20 A 1 L round-bottom flask equipped with a Teflon-coated magnetic stir bar was charged with triphenylphosphine (3 equiv) and dichloromethane (~300 mL). Tetrabromomethane (1.5 equiv) was then added slowly into the reaction mixture, and the reaction mixture was stirred at room temperature until most of the solids dissolved.…”
Section: Methodsmentioning
confidence: 99%
“…Without a Ni catalyst, only a low yield of was obtained (Table S2, entry 16). Nickel(II) precatalysts, Ni II (TMEDA)(o-tolyl)(Cl) 37 and Ni II Br 2 (diglyme), did not efficiently catalyze the reaction as compared to Ni(cod) 2 despite the use of other derivatives of 2,2'-dipyridiyl ligands (Table S2, entries [17][18][19][20][21]. The conditions in entry 14 were used as the optimal general conditions for substrate scope study of aryl halides and other sp 2 -carbon halogen bonds.…”
Section: (B) Optimization Of Ni-catalyzed Cross-coupling Of Alkenylzimentioning
The stereoselective synthesis of trisubstituted alkenes is challenging. Here, we show that an iron‐catalyzed anti‐selective carbozincation of terminal alkynes can be combined with a base‐metal‐catalyzed cross‐coupling to prepare trisubstituted alkenes in a one‐pot reaction and with high regio‐ and stereocontrol. Cu‐, Ni‐, and Co‐based catalytic systems are developed for the coupling of sp‐, sp2‐, and sp3‐hybridized carbon electrophiles, respectively. The method encompasses a large substrate scope, as various alkynyl, aryl, alkenyl, acyl, and alkyl halides are suitable coupling partners. Compared with conventional carbometalation reactions of alkynes, the current method avoids pre‐made organometallic reagents and has a distinct stereoselectivity.
“…20 A 1 L round-bottom flask equipped with a Teflon-coated magnetic stir bar was charged with triphenylphosphine (3 equiv) and dichloromethane (~300 mL). Tetrabromomethane (1.5 equiv) was then added slowly into the reaction mixture, and the reaction mixture was stirred at room temperature until most of the solids dissolved.…”
Section: Methodsmentioning
confidence: 99%
“…Without a Ni catalyst, only a low yield of was obtained (Table S2, entry 16). Nickel(II) precatalysts, Ni II (TMEDA)(o-tolyl)(Cl) 37 and Ni II Br 2 (diglyme), did not efficiently catalyze the reaction as compared to Ni(cod) 2 despite the use of other derivatives of 2,2'-dipyridiyl ligands (Table S2, entries [17][18][19][20][21]. The conditions in entry 14 were used as the optimal general conditions for substrate scope study of aryl halides and other sp 2 -carbon halogen bonds.…”
Section: (B) Optimization Of Ni-catalyzed Cross-coupling Of Alkenylzimentioning
The stereoselective synthesis of trisubstituted alkenes is challenging. Here, we show that an iron‐catalyzed anti‐selective carbozincation of terminal alkynes can be combined with a base‐metal‐catalyzed cross‐coupling to prepare trisubstituted alkenes in a one‐pot reaction and with high regio‐ and stereocontrol. Cu‐, Ni‐, and Co‐based catalytic systems are developed for the coupling of sp‐, sp2‐, and sp3‐hybridized carbon electrophiles, respectively. The method encompasses a large substrate scope, as various alkynyl, aryl, alkenyl, acyl, and alkyl halides are suitable coupling partners. Compared with conventional carbometalation reactions of alkynes, the current method avoids pre‐made organometallic reagents and has a distinct stereoselectivity.
“…1,1-Dibromo-1-alkenes, which are easily derived from aldehydes or ketones with CBr 4 /PPh 3 , are extremely versatile precursors and are often used for synthesizing diverse molecules. [5] Applications of these building block molecules have been extended to the generation of acetylene derivatives, including alkynylphosphonates, [6] ynol ethers, [7] symmetric and asymmetric 1,3-diynes, [8] ynamides, [9] 1,2-diarylacetylenes, [10] ynoate esters, [11] and ynsilanes. [12] Piguel et al proposed a method for copper-catalyzed, C 2 -directed alkynylation of 3H-imidazo [4,5-b]pyridine derivatives using 1,1-dibromo-1-alkenes.…”
An alternative method related to the formation of 3-(hetero)arylpropynamides using palladium/ Cs 2 CO 3 , regiochemically-controlled coupling of isocyanides with 1,1-dibromo-1-alkenes is described. It was found that the presence of palladium is crucial in the media so activated the CÀBr bond in the 1,1-dibromo-1alkenes. Subsequent isocyanide insertion followed by reductive elimination yielded an intermediate that could be easily converted to the desired product in satisfactory yields.
“…[5] Thesubsequent Sonogashira coupling of 19 with trimethylsilylacetylene,followed by desilylation of the coupling product with K 2 CO 3 and methanol, afforded the corresponding terminal alkyne 16 b in quantitative yield. [14] Cadiot-Chodkiewicz coupling [13a] between 16 b and bromoalkyne 17 b [15] afforded the corresponding conjugated diyne 21.T reatment with TMSOTf and 2,6-lutidine [16] led to selective removal of the Boc protecting group,a nd the resulting aniline 22 was then treated with tBuONO and TMSN 3 to give the corresponding azido alkyne 10 d in 87 % yield over three steps from 16 b. [17] Several other conjugated diynes were prepared either in asimilar manner (for 10 a)or by the derivatization of the conjugated diyne 21 (for 10 b,c; see the Supporting information).…”
In total and formal syntheses of dictyodendrins B, C, E, and F, the key step involved the direct construction of the pyrrolo[2,3-c]carbazole core by the gold-catalyzed annulation of a conjugated diyne with a pyrrole to form three bonds and two aromatic rings. The subsequent introduction of substituents at the C1 (Suzuki-Miyaura coupling), C2 (addition to an aldehyde), N3 (alkylation), and C5 positions (Ullman coupling) provided divergent access to dictyodendrins.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.