Copper(ii)-catalyzed and acid-promoted highly regioselective oxidation of tautomerizable C(sp³)–H bonds adjacent to 3,4-dihydroisoquinolines using air (O₂) as a clean oxidant

Abstract

A novel Cu(ii)-catalyzed and acid-promoted highly regioselective oxidation of tautomerizable C(sp3)–H bonds adjacent to 1-Bn-DHIQs was developed. This method was successfully applied in the first total synthesis of canelillinoxine.

Catalyst-Free α-Allylation of Dihydroisoquinolines with Morita–Baylis–Hillman Carbonates and Its Applications in the Construction of Benzo[a]quinolizidines

“…However, with the R = Ph group, the reaction provided the desired product 3ga in a lower yield (56%) than expected, which is probably due to the oxidation at the benzyl position. 21 Besides, other functional groups, such as alkene, ether, and ester, were also compatible with the reaction conditions, allowing for efficient synthesis of multifunctional products in good yields (3ia, 3ja, and 3ka). A variety of electron-donating and -withdrawing groups such as MeO−, Cl−, Br−, and NO 2 − at the aromatic part of 3,4-dihydroisoquinolines were also investigated, giving the desired products 3la−3qa in moderate to good yields (64−93%).…”

“…The sterically hindered alkyl groups such as isopropyl or cyclohexyl groups did not affect the efficiency of the reaction ( 3da , 3ha ). However, with the R = Ph group, the reaction provided the desired product 3ga in a lower yield (56%) than expected, which is probably due to the oxidation at the benzyl position . Besides, other functional groups, such as alkene, ether, and ester, were also compatible with the reaction conditions, allowing for efficient synthesis of multifunctional products in good yields ( 3ia , 3ja , and 3ka ).…”

Protecting group-free synthesis of the fungicide Mandipropamid

“…19 One-pot reduction of both double bonds and the nitro functionality in 3, using lithium aluminium hydride, afforded the desired amine, 4-(2-aminoethyl)-2-methoxyphenol (4) in 73% yield. 20 The carboxylic acid fragment 6 was prepared by a modified Cannizzaro protocol. This started from commercially available, p-chloroacetophenone (5), which was treated with selenium dioxide in the presence of the Lewis acid, ytterbium triflate, in a solvent mixture of dioxane-water (3:1) at 90 °C.…”