Abstract
Reductive functionalization of C–C unsaturated systems, including alkenes and alkynes,
with a range of hydroelements (H[E]) is one of the most fundamental and highly practical
methods for the synthesis of functionalized hydrocarbons. Since the resultant hydrocarbon
products have strong applicability as synthetic intermediates, numerous homogeneous
organo(metallic) catalysts have been intensively utilized to date for reductive functionalization
reactions. In particular, well-defined transition-metal-based catalysts capable of
controlling the regio- or stereoselectivity of a product by harnessing the addition
of H[E] (E = H, B, Si, Ge) into Cα –Cβ unsaturated bonds have drawn special attention. In this review , we describe recent examples of transition-metal catalytic systems (M = Fe, Co, Rh,
Pd, Ni) for regio- or stereodivergent hydroelementation reactions of (conjugated)
alkenes, alkynes, and allenes to give a pair of isomeric products in high selectivities
from the same starting compounds simply by variation of the ligand. Mechanistic aspects
of the ligand-controlled selectivity divergence are discussed in detail on the basis
of experimental observations and/or computational insights.
1 Introduction
2 Hydroelementation of Alkenes and Alkynes
3 Hydroelementation of Conjugated Dienes and Diynes
4 Hydroelementation of Allenes
5 Summary and Outlook
Keywords transition-metal catalysis - hydroelementation - regiodivergence - stereodivergence
- ligand effect - C–C unsaturated systems
