Cooperative Catalysis: Enantioselective Propargylic Alkylation of Propargylic Alcohols with Enecarbamates Using Ruthenium/Phosphoramide Hybrid Catalysts

Abstract

The diastereo- and enantioselective propargylic alkylation of propargylic alcohols with E-enecarbamates in the presence of a catalytic amount of thiolate-bridged diruthenium complexes bearing an optically active phosphoramide moiety gives the corresponding propargylic alkylated products (up to 97 % ee).

Synthesis and structures of a chiral phosphine–phosphoric acid ligand and its rhodium(I) complexes

“…Recently, Nishibayashi et al disclosed an elegant cooperative dual catalysis using diruthenium complexes bearing a chiral phosphoramide group for enantioselective propargylic alkylations of propargylic alcohols with enecarbamates (Scheme 2). 9 This study suggested the importance of ligand-substrate interactions through hydrogen bonding for high enantioselectivity. 10 3 Scheme 1.…”

“…propargylic alkylation of propargylic alcohol with enecarbamate. 9 Herein, we report the synthesis and characterization of a chiral phosphine-phosphoric acid ligand, which possesses both a tertiary phosphine as a metal-coordination site and a BINOL-derived phosphoric acid as a Brønsted acid or an anionic coordination site in the same molecule (Scheme 3). The P,O-chelation properties of the phosphine-phosphoric acid ligands toward rhodium(I) complexes were demonstrated by 4 NMR and single-crystal X-ray diffraction analysis.…”

Scope and advances in the catalytic propargylic substitution reaction

“…Nishibayashi and co-workers in the year 2015 have reported a highly diastereo and enantioselective propargylic alkylation of propargylic alcohols 209 with E-ene-carbamates 274 in the presence of a catalytic amount of a thiolate-bridged diruthenium complex, bearing an optically active phosphoramide moiety, Scheme 121. 156 The authors have designed a hybrid catalyst consisting of a thiolate-bridged diruthenium complex tagged with (R)-BINOL based phosphoramide moiety with the rationale that the ruthenium complex will activate the allenediene intermediate and the phosphoramide will guide the ene-carbamate to control the nucleophilic attack, Fig. 19.…”

“…Nishibayashi and co-workers in the year 2015 have reported a highly diastereo and enantioselective propargylic alkylation of propargylic alcohols 209 with E -ene-carbamates 274 in the presence of a catalytic amount of a thiolate-bridged diruthenium complex, bearing an optically active phosphoramide moiety, Scheme 121 . 156 …”

Recent Advances in Direct Catalytic Dehydrative Substitution of Alcohols

“…175 Quite recently, Nishibayashi and co-workers reported an elegant diastereo-and enantioselective propargylic alkylation of propargylic alcohols with (E)-enecarbamates through the use of a rationally designed thiolate-bridged diruthenium complex bearing a covalently linked chiral phosphoramide moiety. 176…”