151993-29-2Relevant academic research and scientific papers
Sulfones as Synthetic Linchpins: Transition-Metal-Free sp3–sp2 and sp2–sp2 Cross-Couplings Between Geminal Bis(sulfones) and Organolithium Compounds
Trost, Barry M.,Kalnmals, Christopher A.
, p. 9066 - 9074 (2018)
A valuable umpolung strategy that highlights the ambiphilic nature of the bis(phenylsulfonyl)methyl synthon and demonstrates its utility as a synthetic linchpin is reported. Although the bis(phenylsulfonyl)methyl group is typically introduced as an sp3-carbon nucleophile, it is demonstrated that it can also function as an effective sp2-carbon electrophile in the presence of organolithium nucleophiles. Alkyl- and aryllithiums couple with the central carbon of the bis(phenylsulfonyl)methyl unit to ultimately generate trisubstituted alkenes, comprising formal sp3–sp2 and sp2–sp2 cross-couplings between organolithium reagents and bis(sulfones). This process occurs almost instantaneously at ?78 °C in the absence of any transition metals. By developing this curious transformation, it has been demonstrated that bis(phenylsulfonyl)methane is a valuable synthetic linchpin, which can undergo two C?C bond-forming processes as an sp3-nucleophile, followed by a third C?C bond-forming reaction as an effective sp2-electrophile. This discovery significantly enhances the utility of this ubiquitous, but underutilized, linker group.
Gold(I) Complexes with Eight-Membered NHC Ligands: Synthesis, Structures and Catalytic Activity
Cervantes-Reyes, Alejandro,Rominger, Frank,Rudolph, Matthias,Hashmi, A. Stephen K.
supporting information, p. 2523 - 2533 (2020/05/06)
A series of expanded-ring NHC gold complexes of the formula (NaphtDHD?Ar)Au?X (NaphtDHD=4,5-dihydro-1H-naphtho[1,8-ef][1,3]diazocin-3(2H)-ylidene; Ar: Mes=2,4,6-trimethylphenyl, Dipp=2,6-diisopropylphenyl or Xyl=2,6-dimethylphenyl; X=Cl, NCCH3, NTf2) have been synthesized, including the first gold(I) triflimidate complex (5) stabilized by an eight-membered NHC ligand. The new organogold compounds have been characterized by mass spectrometry, IR spectroscopy, and 1H and 13C NMR spectroscopy. The structural geometries of 3 b–c and 5 have been unequivocally established by crystallographic analysis revealing broad N-C-N angles (>121°) and high buried volume values (46–54%). The first catalytic studies were carried out on the cycloisomerization of 1,6-enynes, obtaining full conversions (0.5 mol% catalyst loading) and excellent endo/exo selectivity (up to 99:1), and on the gold-catalyzed phenol synthesis. Lastly, the (NaphtDHD-Dipp)Au+ NTf2? species was subjected to a kinetic experiment in the cyclization of a N-propargyl carboxamide to evaluate the efficiency of the pre-formed catalyst (5) and the in situ activated gold complex (3 b+AgNTf2). (Figure presented.).
Unmasking the 6,7,5-Tricarbocyclic Frame of [5 + 2]/[4 + 2] Pyrone-Alkene Cycloadducts
Rodriguez, J. Ramon,Castedo, Luis,Mascarenas, Jose L.
, p. 2528 - 2531 (2007/10/03)
Opening of the bridging ether of 8-oxabicyclo[3.2.1]oct-6-ene systems 1,7-fused to a five-membered carbocycle that bears a double bond conjugated to that of the oxabicycle can be induced at low temperaure by the addition of an organolithium reagent. If this double bond is unsubstituted, the opening occurs via an anti-1,6-addition pathway, and if substituted it takes place by means of a more classical syn SN2′ addition.
Palladium-Catalyzed 'Metallo-Ene'-Type Cyclization/Vinylstannane Coupling of 1-Acetoxy-octa-2,7-dienes and 1-Acetoxy-oct-2-en-7-ynes
Oppolzer, Wolfgang,Ruiz-Montes, Jose
, p. 1266 - 1274 (2007/10/02)
Palladiumbis(dibenzylideneacetone)/tri(2-furyl)phosphine-catalyzed cyclizations of dienyl acetates 2 in the presence of an (1-alkenyl)(tributyl)stannane and ZnCl2 provided trans-substituted 3-alkenyl-4-vinylcyclopentanes 11 in good yields.Analogous intram
