Regioselective (Diacetoxyiodo)benzene-Promoted Halocyclization of Unfunctionalized Olefins

Abstract

A metal-free method for intramolecular halocyclization of unfunctionalized olefins was detailed. (Diacetoxyiodo)benzene (PIDA) was very effective for haloamidation, haloetherification, and halolactonization of unfunctionalized olefins. In the presence of 1.1 equiv of PIDA and suitable halogen sources, a variety of unfunctionalized olefins could be converted to the corresponding 1,2-bifunctional cyclic skeletons in good to excellent isolated yields, and key intermediates for biologically interesting compounds could be obtained in high yields under mild conditions via nucleophilic substitution of the thus obtained halocyclization products.

Intramolecular Aminoboration of Unfunctionalized Olefins

“…In the course of searching for new methods for the amination of CC multiple bonds, we found that the intramolecular fluoroamination of unfunctionalized olefins was possible with BF 3 as the fluorine source and PhI(OAc) 2 as the reaction promoter 12. We assumed that the direct aminoboration of CC double bonds should be possible if an NB intermediate could be generated during the reaction.…”

Fluorination and Fluoroalkylation Reactions Mediated by Hypervalent Iodine Reagents

“…Liu and coworkers pioneeringly disclosed a regioselective palladium-catalyzed intramolecular oxidative aminofluorination of unactivated alkenes (22), in which AgF was employed as a fluorination reagent in the presence of PhI(OPiv) 2 (Scheme 5). [15] The transformation offered a very efficient method to prepare fluorine-containing cyclic amines (23). To understand the possible reaction mechanisms, deuterium-labeled alkene E-22 a-d1 was subjected to the standard aminofluorination conditions, and the reaction afforded a mixture of trans-23 a-d1 and cis-23 a-d1 in 79% yield with a 72:28 ratio.…”

“…Similarly, a metal-free intramolecular aminofluorination of unfunctionalized olefins with Et 2 O • BF 3 and PhI(OAc) 2 was detailed. [23] The corresponding fluoroamidation products were obtained only when Et 2 O • BF 3 was employed rather than conventional metal fluorides or other fluorine sources. The reactions finished in minutes and gave the endo 3-fluoropiperidine products as the sole isomers in moderate yields, but with varied amounts of 3-acetoxypiperidines.…”

Enantioselective Synthesis of 2‐Bromomethyl Indolines via BINAP(S)‐Catalyzed Bromoaminocyclization of Allyl Aniline

“…( R )‐2‐(bromomethyl)‐5‐fluoro‐1‐tosylindoline (7m) . Yield: 30.6 mg, 80%, light yellow solid, mp: 108–109 °C.…”