Quantitative analysis of steric effects on the regioselectivity of the Larock heteroannulation reaction

Abstract

Alkylphenylacetylene derivatives were synthesized and used as reactants in the Larock heteroannulation reaction to investigate the steric influence on regioselectivity. Large alkyl groups preferentially yielded 2-alkyl-3-phenylindole products, while smaller alkyl...

Cross-coupling of organic fluorides with allenes: a silyl-radical-relay pathway for the construction of α-alkynyl-substituted all-carbon quaternary centres

“…First, a gram-scale reaction of 1a and 3a proceeded smoothly to afford 4aa in 68% yield under the standard conditions in the presence of Et 3 SiBpin. Thereafter, a dual catalyst (Pd(OAc) 2 /PPh 3 and CuI) enabled the cross-coupling reaction of 4aa with a substituted arylbromide, 27 which furnished the phenyl-coupling product 8 (95% yield) in the presence of Et 3 N in THF at 80 °C. Treatment of 4aa with trimethylsilyl chloride (TMS-Cl) in the presence of butyllithium furnished TMS-acetylene product 9 (95% yield).…”