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Silylformylation of Chiral 1‐Alkynes, Catalysed by Solvated Rhodium Atoms
Author(s) -
Aronica Laura Antonella,
Terreni Silvia,
Caporusso Anna Maria,
Salvadori Piero
Publication year - 2001
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/1099-0690(200111)2001:22<4321::aid-ejoc4321>3.0.co;2-t
Subject(s) - chemistry , alkyne , rhodium , stereocenter , hydrosilylation , moiety , steric effects , medicinal chemistry , catalysis , chemoselectivity , carbon monoxide , triple bond , enantioselective synthesis , silane , double bond , stereochemistry , organic chemistry
Solvated rhodium atoms, prepared by the metal vapour synthesis technique, promote the silylformylation reaction of variously substituted alkynes R 1 R 2 CH(CH 2 ) n C≡CH, with catalytic activities comparable with and even higher than more common species such as Rh 4 (CO) 12 . Z ‐Silylalkenals are exclusively formed in high yields (60−95%) indicating syn addition both of CO and of the silane (Me 2 PhSiH) to the triple bond. The chemoselectivity of the process (silylformylation vs. hydrosilylation) is highly affected by the amount of catalyst employed (mmol of Rh species with respect to the alkyne reagent), by the steric requirements of the acetylenic substrates and by the hydrosilane/alkyne molar ratio. When optically active acetylenes are treated in the presence of Me 2 PhSiH under carbon monoxide pressure, the silylformylation reaction occurs with total retention of stereochemistry of the stereogenic centre, even if it is at the α‐position of the unsaturated moiety, to afford enantiomerically enriched β‐silylalkenals.