Palladium-catalyzed and samarium-promoted coupling of stereochemically-biased allylic acetates with carbonyl compounds

Total Synthesis of Δ12‐Prostaglandin J3, a Highly Potent and Selective Antileukemic Agent

“…Scheme summarizes the formation of advanced intermediate 2 starting from commercially available 2‐cyclopentenone ( 8 ) via intermediates 9 and 10 . By modifying reported procedures,8 8 was first converted to cyclopentenol acetate 9 (DIBAL‐H reduction followed by acetylation, 62 % overall yield; similar results were obtained with LiAlH 4 or NaBH 4 /CeCl 3 as reducing agents, see the Supporting Information), and thence to dimethyl ester 10 through a palladium‐catalyzed Tsuji–Trost asymmetric coupling reaction9 with dimethyl malonate (DMM) in the presence of catalytic amounts of [η 3 ‐C 3 H 5 PdCl] 2 and ( S , S )‐DACH‐phenyl Trost ligand and Cs 2 CO 3 (71 % yield, 97 % ee 10). Monodecarboxylation of 10 (KI, 130 °C) then furnished intermediate 4 in 94 % yield.…”

Molecular Features of the YAP Inhibitor Verteporfin: Synthesis of Hexasubstituted Dipyrrins as Potential Inhibitors of YAP/TAZ, the Downstream Effectors of the Hippo Pathway

“…Our first strategy to obtain dipyrrin 1 (Scheme 1) was inspired by the total synthesis of hematoporphyrin published by Martine tal. [16] Thec ondensation of the two pyrrolo units (2 [17] and 3 [18] )u sing HBr in acetic acid gave dipyrrin 4 in high yield (89 %), but reduction of the acetylg roup in the presence of NaBH 4 [15] alone or with CeCl 3 , [19] yieldedd ipyrromethane 5' instead of the expected alcohol (5).…”

Total Synthesis of Δ12‐Prostaglandin J3, a Highly Potent and Selective Antileukemic Agent

“…Scheme 1 summarizes the formation of advanced intermediate 2 starting from commercially available 2-cyclopentenone (8) via intermediates 9 and 10. By modifying reported procedures, [8] 8 was first converted to cyclopentenol acetate 9 (DIBAL-H reduction followed by acetylation, 62 % overall yield; similar results were obtained with LiAlH 4 or NaBH 4 / CeCl 3 as reducing agents, see the Supporting Information), and thence to dimethyl ester 10 through a palladium-catalyzed Tsuji-Trost asymmetric coupling reaction [9] with dimethyl malonate (DMM) in the presence of catalytic amounts of [h 3 -C 3 H 5 PdCl] 2 and (S,S)-DACH-phenyl Trost ligand and Cs 2 CO 3 (71 % yield, 97 % ee [10] ). Monodecarboxylation of 10 (KI, 130 8C) then furnished intermediate 4 in 94 % yield.…”