title: Enantioselective formal hydration of α,β-unsaturated acceptors: asymmetric conjugate addition of silicon and boron nucleophiles.
abstract: The direct enantioselective 1,4-addition of water to α,β-unsaturated acceptors is an open challenge in asymmetric catalysis. Enantioselective conjugate addition of either silicon or boron nucleophiles and subsequent enantiospecific oxidative degradation of the carbon-element bond represents, however, an attractive detour. A single extra step thereby enables an indirect enantiocontrolled construction of (in a broader sense) aldols from α,β-unsaturated carbonyl and carboxyl compounds. While that strategy had been obvious for a long time, it was recent stunning progress in transition metal-catalysed activation of interelement linkages that brought about the solution to that long-standing problem. A concise introduction of existing protocols for stereoselective 1,4-addition of oxygen nucleophiles is followed by a comprehensive summary of the recent rapid advances in transition metal-catalysed (and metal-free) asymmetric conjugate transfer of nucleophilic silicon and boron onto α,β-unsaturated acceptors.
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität, Corrensstrasse 40, D-48149 Münster, Germany.
authors.forename: Eduard
authors.initials: E
authors.lastname: Hartmann
authors.forename: Devendra J
authors.initials: DJ
authors.lastname: Vyas
authors.forename: Martin
authors.initials: M
authors.lastname: Oestreich