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Synthesis of novel stereodefined vinylgermanes bearing an allyl group or an allenyl group: ( E )‐2‐aryl‐1‐germylalka‐1,4‐dienes and ( E )‐4‐aryl‐5‐germylpenta‐1,2,4‐trienes
Author(s) -
Kato Kotaro,
Senda Yoshiya,
Makihara Yoshiaki,
Kojima Takeshi,
Kurihara Hiroyuki,
Takahashi Yutaka,
Nakano Taichi
Publication year - 2007
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.1264
Subject(s) - chemistry , aryl , bromide , allylic rearrangement , medicinal chemistry , allyl bromide , propargyl bromide , propargyl , iodide , halide , stereochemistry , organic chemistry , alkyl , catalysis
Abstract Stereodefined synthesis of an unprecedented family of vinylgermanes bearing an allyl group, ( E )‐2‐aryl‐1‐germylalka‐1,4‐dienes, or an allenyl group, ( E )‐4‐aryl‐5‐germylpenta‐1,2,4‐trienes, via a cross‐coupling reaction of ( Z )‐germyl(stannyl)ethenes with the respective allyl halide (Br, Cl) and propargyl bromide is described. In the reaction with allyl halides, either a Pd(dba) 2 –CuI combination (dba: dibenzylideneacetone) or CuI alone readily catalyzes or mediates the coupling reaction of ( Z )‐germyl(stannyl)ethenes, producing the novel vinylgermanes bearing an allyl group. The thienyl group or hydroxy group of the ( Z )‐germyl(stannyl)ethene survives the reaction. Copper(I) iodide alone readily mediates the reaction with allyl chloride or methallyl chloride upon addition of sodium bromide to produce the respective cross‐coupled product in good yield. In contrast, crotyl halides (Br, Cl) or prenyl chloride couple with/without allylic transposition in the bromide or the chloride. In the reaction with propargyl bromide, a Pd(dba) 2 and CuI combination efficiently drives the coupling reaction of ( Z )‐germyl(stannyl)ethenes in NMP ( N ‐methylpyrrolidone), providing the stereochemically defined allenyl vinylgermanes, ( E )‐4‐aryl‐5‐germylpenta‐1,2,4‐trienes, in good yields. Copyright © 2007 John Wiley & Sons, Ltd.