Substrate directed diastereoselective hydroformylation of acyclic homomethallylic alcohols
作者:Bernhard Breit
DOI:10.1039/a608612h
日期:——
Diastereoselective hydroformylation of acyclic homomethallylic alcohols
with the aid of a catalyst directing group is achieved and the
stereochemical outcome of this reaction is rationalized by analysing the
preferred substrate conformation in solution.
Rhodium-catalyzed hydroformylation in the presence of stabilizedphosphorusylides initiates a domino hydroformylation–Wittig olefination process. When mono-substituted acceptor-stabilized phosphorusylides were employed, a hydrogenation step succeeds the Wittig olefination to give a domino hydroformylation–Wittig olefination hydrogenation process. For the hydroformylation key step both, linear regioselective
Methallyl and homomethallyl alcohols can undergo stereoselective hydroformylation-Wittig and hydroformylation-Wittig-hydrogenation reactions in one-pot domino processes. This sequential transformation allows the formation of C-C bonds and the generation of a new stereogenic center, and gives preparatively interesting compounds [Eq. (a)]. The reaction products are obtained in satisfactory to good yields and in diastereoselectivities of 90:10 to >98:2. CDG=catalyst-directing group; R'=H; R″=OEt, Me.