Palladium‐Catalyzed Enantioselective Heck Carbonylation with a Monodentate Phosphoramidite Ligand: Asymmetric Synthesis of (+)‐Physostigmine, (+)‐Physovenine, and (+)‐Folicanthine

Abstract

Reported herein is the development of the first enantioselective monodentate ligand assisted Pd-catalyzed domino Heck carbonylation reaction with CO.T he highly enantioselective domino Heck carbonylation of N-aryl acrylamides and various nucleophiles,i ncluding arylboronic acids, anilines,a nd alcohols,i nt he presence of CO was achieved. A novel monodentate phosphoramidite ligand, Xida-Phos,h as been developed for this reaction and it displays excellent reactivity and enantioselectivity.T he reaction employs readily available starting materials,tolerates awide range of functional groups,and provides straightforwardaccess to adiverse array of enantioenriched oxindoles having b-carbonyl-substituted all-carbon quaternary stereocenters,thus providing afacile and complementary method for the asymmetric synthesis of bioactive hexahydropyrroloindole and its dimeric alkaloids. Recently,ahighly enantioselective Pd-catalyzed Heck-Matsuda carbonylation of aryldiazonium salts and Heck-carbonylative spirocyclization were developed by the groups of Correia and Luo and Zhu, respectively,b yu sing bidentate bisoxazole or bisphosphine ligands. [14] Notwithstanding,t he use of either aryldiazonium salts or intramolecular nucleophiles is mandatory.Given the high reactivity of monodentate Scheme 1. Enantioselective Pd-catalyzed domino Heck carbonylation and HPI alkaloides synthesis.

Efficient access to aliphatic esters by photocatalyzed alkoxycarbonylation of alkenes with alkyloxalyl chlorides

“…Furoindoline moiety is broadly found in the core structure of biologically active compounds and natural products [37][38][39][40][41][42][43][44] . Considering that oxindole-3-acetates are versatile building blocks for constructing heterocycle-fused indolines 45,46 , we decided to apply the above method to the preparation of furoindoline derivatives. As shown in Fig.…”

Noncovalent CH–π and π–π Interactions in Phosphoramidite Palladium(II) Complexes with Strong Conformational Preference

“…Such heterocomplexes can be useful in synthetic chemistry, because they can display increased activity or selectivity in metal‐catalyzed reactions, especially in rhodium‐catalyzed hydrogenations and conjugate additions [33–39] . On the other hand, palladium phosphoramidite complexes catalyze challenging allylic substitutions and domino‐Heck reactions, and mechanistic insight would be welcome [19, 40–42] . In addition, the experimental data about the relative energetics of these complexes allowed us to select and validate a suitable computational method, which could be potentially applied in the design of other TM systems.…”

Nickel-catalyzed asymmetric reductive aryl-allylation of unactivated alkenes

“…Hitherto, the successfully installed carbo-moieties following this reaction sequence include alkyl, 2–4 aryl, 4–6 benzyl, 7 alkenyl, 4,8 alkynyl, 9 and carbonyl. 10 However, transition-metal catalyzed highly enantioselective olefin carbo-allylation still remains elusive mainly due to the issues in controlling chemo-, regio-, and stereo-selectivity. 11,12 …”