Phosphine catalysis of allenes with electrophiles

Abstract

Nucleophilic phosphine catalysis of allenes with electrophiles is one of the most powerful and straightforward synthetic strategies for the generation of highly functionalized carbocycle or heterocycle structural motifs, which are present in a wide range of bioactive natural products and medicinally important substances. The reaction topologies can be controlled through a judicious choice of the phosphine catalyst and the structural variations of starting materials. This Tutorial Review presents selected examples of nucleophilic phosphine catalysis using allenes and electrophiles.

Scheme 1

Typical allenes and electrophiles used in nucleophilic phosphine catalysis

Scheme 2

Mechanism of allene–olefin [3+2] annulation

Scheme 3

Intramolecular allene–olefin [3+2] annulation

Scheme 4

Synthesis of spiro(cyclopenten)oxindoles through allene–olefin [3+2] annulation

Scheme 5

Mechanism of allene–alkene [4+2] annulation

Scheme 6

Phosphine-catalyzed imine [3+2] annulation of γ-substituted allenoates

Scheme 7

Synthesis of benzo-fused cyclic sulfamide heterocycles through allene–imine [3+2] annulation

Scheme 8

Synthesis of (±)-alstonerine, (±)-macroline, and (±)-hirsutine through allene–imine [4+2] annulation

Scheme 9

Construction of nitrogen heterocycle libraries through phosphine-catalyzed allene–imine [3+2] and [4+2] annulations

Scheme 10

Nucleophilic phosphine catalysis of allenes with aldehydes

Scheme 11

Mechanism of chromone–allene [4+3] annulation

Scheme 12

Mechanism of allene–aziridine [3+3] annulation

Scheme 13

Mechanism of allene–allene–azomethine imine [3+2+3] annulation

Scheme 14

Typical chiral phophines used in nucleophilic phosphine catalysis

Scheme 15

Enantioselective total synthesis of (+)-ibophyllidine through asymmetric phosphine-catalyzed allene-imine [3+2] annulation