77341-51-6Relevant academic research and scientific papers
Switchable selectivity in Pd-catalyzed [3 + 2] annulations of γ-oxy-2-cycloalkenones with 3-oxoglutarates: C-C/C-C vs C-C/O-C bond formation
Liu, Yang,Oble, Julie,Poli, Giovanni
supporting information, p. 1107 - 1115 (2019/06/08)
Two complementary [3 + 2] annulation protocols between 3-oxoglutarates and cyclic γ-oxy-2-cycloalkenones, simply differing on the reaction temperature, are disclosed. These domino transformations allow C-C/O-C or C-C/C-C [3 + 2] annulations at will, via an intermolecular Pd-catalyzed C-allylation/intramolecular O- or C-1,4-addition sequence, respectively. In particular, exploiting the reversibility of the O-1,4-addition step, in combination with the irreversible C-1,4-addition/decarboxylation path, the intramolecular conjugate addition step could be diverted from the kinetic (O-alkylation) to the thermodynamic path (C-alkylation) thanks to a simple temperature increase. Crucial for the success of this bis-nucleophile/bis-electrophile [3 + 2] annulation is its well-defined step chronology in combination with the total chemoselectivity of the former step. This [3 + 2] C-C/O-C bond forming annulation protocol could be also extended to 1,3,5-triketones as well as 1,3-bis-sulfonylpropan-2-one bis-nucleophiles.
Palladium-Catalyzed [3 + 2]-C-C/N-C Bond-Forming Annulation
Liu, Yang,Mao, Zhongyi,Pradal, Alexandre,Huang, Pei-Qiang,Oble, Julie,Poli, Giovanni
supporting information, p. 4057 - 4061 (2018/07/15)
The synthesis of bi- and tricyclic structures incorporating pyrrolidone rings is disclosed, starting from resonance-stabilized acetamides and cyclic α,β-unsaturated-γ-oxycarbonyl derivatives. This process involves an intermolecular Tsuji-Trost allylation/intramolecular nitrogen 1,4-addition sequence. Crucial for the success of this bis-nucleophile/bis-electrophile [3 + 2] annulation is its well-defined step chronology in combination with the total chemoselectivity of the former step. When the newly formed annulation product carries a properly located o-haloaryl moiety at the nitrogen substituent, a further intramolecular keto α-arylation can join the cascade, thereby forming two new cycles and three new bonds in the same synthetic operation.
4-Hydroxycyclopent-2-en-1-one and derivatives as chiral synthetic equivalents of cyclopentadienone in asymmetric Diels-Alder reactions
Dols,Klunder,Zwanenburg
, p. 8515 - 8538 (2007/10/02)
Endo-tricyclodecadienone 8a and related annelated-cyclopentenones (8b, 20, 21a-c and 22) are synthesized in good chemical yield by a Diels-Alder reaction of 4-hydroxycyclo-pent-2-en-1-one 12a and derivatives 12b-h with an appropriate diene. These additions are considerably accelerated by Lewis catalysts, high pressure and by using water as solvent. Due to opposing steric and electronic effects the diastereofacial selectivity of the asymmetric cycloadditions is moderate. By carefully choosing the substrate and reaction conditions an acceptable π-facial selectivity can be achieved.
STEREOCHEMICAL STUDIES - LVII. SYNTHESIS OF OPTICALLY ACTIVE COMPOUNDS BY THE NOVEL USE OF MESO-COMPOUNDS -1. EFFICIENT SYNTHESIS OF TWO STRUCTURAL TYPES OF OPTICALLY PURE PROSTAGLANDIN INTERMEDIATES.
Nara, M,Terashima, S.,Yamada, S.
, p. 3161 - 3170 (2007/10/02)
With an aim to overcome several inefficient aspects of ordinary methods of preparing optically active compounds, we have developed a new method which recommends utilization of symmetrically functionalized meso-compounds in place of racemic compounds.As shown in Scheme 1, when the meso-compound (I) is monofunctionalized by an optically active functional group (A) and each of the formed diastereomers (II and III) is subjected to further chemical elaborations including protective group transposition, it is theoretically possible to convert the total amount of the starting material (I) into the requisite optically pure product (VI or VII) by selecting synthetic schemes.By employing this novel concept, two structural types of the prostaglandin intermediates ((-)- and (+)-2a,b) have been prepared from the meso-diols (1a,b) by way of the two diastereomeric monoesters (13a,b and 14a,b) which are produced by the reactions 1a,b with N-mesyl- and N-phthaloyl-(S)-phenylalanyl chloride (3a,b).
