The directed ortho-lithiation of lithium phenylsulfide and lithium phenylselenide plus sigma-aromaticity and the hexakis(phenylseleno)benzene dication
type: CreativeWork
description: The directed ortho-lithiation of lithium phenylselenide by reaction with $n$-butyllithium in cyclohexane with $N$,$N$,$N\sp\prime$,$N\sp\prime$-tetramethylethylenediamine gives almost quantitative conversion to lithium 2-lithiobenzeneselenolate and is estimated to be seven to eight times faster than the directed ortho-lithiation of lithium phenylsulfide to form lithium 2-lithiobenzenethiolate. Treatment of the lithium 2-lithiobenzeneselenolate with a variety of electrophiles (D$\sb2$O, carbon dioxide, selenium, methylene chloride, methyl iodide, thioxanthone, and dimethylcarbonate) form ortho-substituted products. The treatment of dilithium benzene-1,2-diselenolate with methylene chloride and 1,2-dibromoethane forms 1,3-benzodiselenole (70.4% yield) and dihydro-1,4-benzodiselenin (54.6% yield), respectively. The ortho-lithiation and $o,o\sp\prime$-dilithiation of dilithium benzene-1,2-diselenolate is presented. The adduct to thioxanthone is ring-closed to form the (1) benzoselenopyrano (2,3,4-kl) thioxanthylium cation and 13b$H$- (1) benzoselenopyrano (2,3,4-kl) thioxanthen-13b-ol (13.3% yield).
abstract: The directed ortho-lithiation of lithium phenylselenide by reaction with $n$-butyllithium in cyclohexane with $N$,$N$,$N\sp\prime$,$N\sp\prime$-tetramethylethylenediamine gives almost quantitative conversion to lithium 2-lithiobenzeneselenolate and is estimated to be seven to eight times faster than the directed ortho-lithiation of lithium phenylsulfide to form lithium 2-lithiobenzenethiolate. Treatment of the lithium 2-lithiobenzeneselenolate with a variety of electrophiles (D$\sb2$O, carbon dioxide, selenium, methylene chloride, methyl iodide, thioxanthone, and dimethylcarbonate) form ortho-substituted products. The treatment of dilithium benzene-1,2-diselenolate with methylene chloride and 1,2-dibromoethane forms 1,3-benzodiselenole (70.4% yield) and dihydro-1,4-benzodiselenin (54.6% yield), respectively. The ortho-lithiation and $o,o\sp\prime$-dilithiation of dilithium benzene-1,2-diselenolate is presented. The adduct to thioxanthone is ring-closed to form the (1) benzoselenopyrano (2,3,4-kl) thioxanthylium cation and 13b$H$- (1) benzoselenopyrano (2,3,4-kl) thioxanthen-13b-ol (13.3% yield).
author: Loop, Cynthia Kay
language: eng
keywords: Chemistry, Organic
date published: 2011-05-07T13:23:54Z
date modified: 2026-07-22T22:25:19Z
provider: University of Illinois - Urbana-Champaign
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Illinois at Urbana-Champaign

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2142/21941