Sequential Carbon–Carbon/Carbon–Selenium Bond Formation Mediated by Iron(III) Chloride and Diorganyl Diselenides: Synthesis and Reactivity of 2-Organoselenyl-Naphthalenes

Abstract

In this paper, we report an intramolecular cyclization of benzylic-substituted propargyl alcohols promoted by iron(III) chloride and diorganyl diselenides to give 2-organoselenyl-naphthalenes via a sequential carbon-carbon/carbon-selenium bond formation. The present reaction tolerated a wide range of substituents in both propargyl alcohols and diorganyl diselenides to give the desired 2-organoselenyl-naphthalenes in good yields with high selectivity. In addition, O-acyl protected propargyl alcohol and propargyl bromide were also subjected to this protocol giving the corresponding 2-organoselenyl-naphthalenes. We found that dichalcogenide species affected the formation of cyclized products, whereas diorganyl diselenides gave high yields, moderate yields were obtained with diorganyl disulfides, and no product formation was found with diorganyl ditellurides. The key transformations could be attributed to the carbon-carbon triple bond activation of benzylic-substituted propargyl alcohols by a seleniranium ion, antiattack of the electron cloud from the aromatic ring at the activated triple bond, and cyclization via an exclusive 6-endo-dig process. We also found that the corresponding 2-organoselenyl-naphthalenes are suitable substrates to the selenium-lithium exchange reactions followed by trapping with aldehydes affording the corresponding secondary alcohols.

Peer Review #3 of "Ultrasound-promoted synthesis of 2-organoselanyl-naphthalenes using Oxone® in aqueous medium as an oxidizing agent (v0.1)"

“…Based on our results and those from the literature (Zhang, Sarkar & Larock, 2006;Recchi, Back & Zeni, 2017;Perin et al, 2018), a plausible mechanism for the carbocyclization of alkynol 1a with (C 6 H 5 Se) 2 2a/Oxone ® in aqueous medium is depicted in Scheme 2. The first step in the reaction is the oxidative cleavage of the Se-Se bond in diphenyl diselenide 2a by Oxone ® , forming intermediates A and B (Perin et al, 2018).…”

“…Manuscript to be reviewed of aryl enynes (Yang et al, 2014), (ii) metal-catalyzed direct selenylation of naphthylboronic acids (Mohan et al, 2015), (iii) cyclization reactions of 4-arylbut-3-yn-2-ols with electrophilic selenium species, like PhSeBr (Zhang, Sarkar & Larock, 2006) or PhSeSePh/FeCl 3 system (Recchi, Back & Zeni, 2017), (iv) [4+2] cycloaddition reaction of chalcogenoalkynes with o-alkynylbenzaldehydes (Mantovani, Back & Zeni, 2012) and (v) oxidative C(sp 3 )-/Se coupling in tetralones (Prasad, Sattar & Kumar, 2017). Despite these are efficient methodologies, chlorinated or high boiling point solvents, harsh base, transition metal catalysts and/or halogenating reagents are involved in the synthesis.…”

Design and Preparation of Poly‐Selenides: Easily Fabricated and Efficient Organoselenium Materials for Heavy Metal Removing and Recycling

“…Yet, selenium chemistry has attracted chemists for a long time, mainly because of the particular bioactivities of the organoselenium compounds as well as their versatile reactivities in organic synthesis . Recently, the green‐side of selenium began to be realized and organoselenium‐catalyzed reactions drew much attention for their application potential in industrial productions .…”

A cost‐effective shortcut to prepare organoselenium catalysts via decarboxylative coupling of phenylacetic acid with elemental selenium

“…Organoselenium compounds have been widely employed in biochemistry, medicinal chemistry, organic synthesis and materials science for their unique bioactivities and chemical activities . Recently, much attention has been paid to the eco‐friendly aspects of organoselenium chemistry and among reported works, organoselenium catalysis is one of the most important research directions for its clean procedures, transition‐metal‐free reaction conditions and the metabolizable catalytic Se element that affords a potential alternative to transition metal catalysts .…”