Premium
Cooperative Catalysis of Metal and OH⋅⋅⋅O/sp 3 ‐CH⋅⋅⋅O Two‐Point Hydrogen Bonds in Alcoholic Solvents: Cu‐Catalyzed Enantioselective Direct Alkynylation of Aldehydes with Terminal Alkynes
Author(s) -
Ishii Takaoki,
Watanabe Ryo,
Moriya Toshimitsu,
Ohmiya Hirohisa,
Mori Seiji,
Sawamura Masaya
Publication year - 2013
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201301280
Subject(s) - catalysis , chemistry , enantioselective synthesis , hydrogen bond , substrate (aquarium) , ligand (biochemistry) , medicinal chemistry , transition metal , hydrogen , combinatorial chemistry , photochemistry , stereochemistry , organic chemistry , molecule , biochemistry , oceanography , receptor , geology
Catalyst–substrate hydrogen bonds in artificial catalysts usually occur in aprotic solvents, but not in protic solvents, in contrast to enzymatic catalysis. We report a case in which ligand–substrate hydrogen‐bonding interactions cooperate with a transition‐metal center in alcoholic solvents for enantioselective catalysis. Copper(I) complexes with prolinol‐based hydroxy amino phosphane chiral ligands catalytically promoted the direct alkynylation of aldehydes with terminal alkynes in alcoholic solvents to afford nonracemic secondary propargylic alcohols with high enantioselectivities. Quantum‐mechanical calculations of enantiodiscriminating transition states show the occurrence of a nonclassical sp 3 ‐CH⋅⋅⋅O hydrogen bond as a secondary interaction between the ligand and substrate, which results in highly directional catalyst–substrate two‐point hydrogen bonding.