1 3
Topics in Current Chemistry (2019) 377:23
formation to form β-amino aldehydes 153 with high level of anti-, diastereo- and
enantioselectivities (up to 99% ee). Finally, a formyl reduction by NaBH 4 /methyl
alcohol yielded the β-amino alcohol compounds 154.
8 Conclusions and Prospects
In this chapter, we have provided an overview of the development and applications of organic phosphoric acids in combination with different first-row transition metals in asymmetric catalysis, providing a mechanistic discussion to better
understand the interaction of the metal/phosphate and the factors for asymmetric
control. The combination of metal cations/complexes with phosphates provides a
variety of catalytic modes, including relay catalysis, counterion-pairing catalysis,
and binary-acid catalysis, thus enabling a range of enantioselective transformations. This progress represents an essential part of the implement of asymmetric
counteranion-directed catalysis reported so far. In addition, concerning the property of metals, e.g., copper, iron, and manganese can act as one or two-electron
transfer catalysts to permit redox reactions. Significant efforts in enantioselective
oxidations and hydrogenations, C–H bond functionalizations and radical-initiated
difunctionalizations of olefins have been made recently. Consequently, the complexity and diversity of the catalytic systems between first-row transition metals and phosphate derivatives potentially provide a powerful, viable and accessible route for asymmetric synthesis, although it is still less developed and limited
to some transition metals. Due to the versatility of metal Lewis acids and chiral
Brønsted acids, the dual metal-CPA catalysis is bound to stimulate more evolutionary research in the future, especially in the field of radical-involved enantioselective chemistry, which remains largely underdeveloped.
Scheme 39 Alkene isomerization/enantioselective aza-Petasis–Ferrier rearrangement reaction of hemiamial vinyl ethers
Reprinted from the journal
181
Topics in Current Chemistry (2019) 377:23
formation to form β-amino aldehydes 153 with high level of anti-, diastereo- and
enantioselectivities (up to 99% ee). Finally, a formyl reduction by NaBH 4 /methyl
alcohol yielded the β-amino alcohol compounds 154.
8 Conclusions and Prospects
In this chapter, we have provided an overview of the development and applications of organic phosphoric acids in combination with different first-row transition metals in asymmetric catalysis, providing a mechanistic discussion to better
understand the interaction of the metal/phosphate and the factors for asymmetric
control. The combination of metal cations/complexes with phosphates provides a
variety of catalytic modes, including relay catalysis, counterion-pairing catalysis,
and binary-acid catalysis, thus enabling a range of enantioselective transformations. This progress represents an essential part of the implement of asymmetric
counteranion-directed catalysis reported so far. In addition, concerning the property of metals, e.g., copper, iron, and manganese can act as one or two-electron
transfer catalysts to permit redox reactions. Significant efforts in enantioselective
oxidations and hydrogenations, C–H bond functionalizations and radical-initiated
difunctionalizations of olefins have been made recently. Consequently, the complexity and diversity of the catalytic systems between first-row transition metals and phosphate derivatives potentially provide a powerful, viable and accessible route for asymmetric synthesis, although it is still less developed and limited
to some transition metals. Due to the versatility of metal Lewis acids and chiral
Brønsted acids, the dual metal-CPA catalysis is bound to stimulate more evolutionary research in the future, especially in the field of radical-involved enantioselective chemistry, which remains largely underdeveloped.
Scheme 39 Alkene isomerization/enantioselective aza-Petasis–Ferrier rearrangement reaction of hemiamial vinyl ethers
Reprinted from the journal
181