ChemInform Abstract: Chiral N‐Heterocyclic Carbene Ligand Enabled Nickel(0)‐Catalyzed Enantioselective Three‐Component Couplings as Direct Access to Silylated Indanols.

Abstract

The title reaction between norbornene derivatives, aromatic aldehydes, and silanes provides silyl protected indanol scaffolds as single diastereomers with high enantiomeric excess.

Catalytic Enantioselective Transformations Involving C–H Bond Cleavage by Transition-Metal Complexes

“…In 2016, the Cramer group reported the first, and currently only, example of an enantioselective Ni-catalyzed aryl C−H functionalization reaction (Scheme 97). 276 Novel C 2 -symmetric NHC L77 was found to provide modest-to-high levels of enantiocontrol (69−91% ee) and complete diastereocontrol for the three-component coupling of aromatic aldehydes 451, norbornenes 452, and silanes 453 (originally reported in a racemic fashion by Ogata, Fukuzawa, and their co-workers 277 ). During reaction optimization studies, a variety of established NHC ligands were initially screened in the coupling of benzaldehyde, norbornene, and triisopropylsilane, including Kundig ligand L78, 278 Glorius's IBiox L79, 279 sponding silylated indanol 454a in 99% yield and 43% ee.…”

3d Transition Metals for C–H Activation

“…Furthermore, similar oxanickelacycles can efficiently react with reductants, such as silanes, organoboranes, or organozincs, being proposed as key intermediates for many nickel(0)-catalyzed reductive couplings. 1203−1206 Subsequently, the group of Cramer 1207,1208 developed the asymmetric nickel(0)-catalyzed hydrocarbamoylation of homoallylic formamides 896 (Scheme 477). 1183 Thus, a novel class of chiral heteroatom secondary phosphine oxide (HASPO) 1181,1209 Moreover, Zhou and co-workers developed an intermolecular nickel-catalyzed hydroacylation reaction of alkenes, including styrene derivatives 75 and terminal aliphatic alkenes 4, with unactivated aldehydes 167 (Scheme 479).…”