Trisubstituted olefin synthesis via Ni-catalyzed hydroalkylation of internal alkynes with non-activated alkyl halides

2018 ◽  
Vol 54 (35) ◽  
pp. 4417-4420 ◽  
Author(s):  
Xiao-Yu Lu ◽  
Mei-Lan Hong ◽  
Hai-Pin Zhou ◽  
Yue Wang ◽  
Jin-Yu Wang ◽  
...  
Keyword(s):  
Stereoselective Synthesis ◽  
Alkyl Halides ◽  
Olefin Synthesis ◽  
Internal Alkynes

The stereoselective synthesis of tri-substituted alkenes is challenging.

C(sp3)–H Alkenylation Catalyzed by Cationic Alkylhafnium Complexes: Stereoselective Synthesis of Trisubstituted Alkenes from 2,6-Dimethylpyridines and Internal Alkynes

2016 ◽  
Vol 35 (22) ◽  
pp. 3816-3827 ◽  
Author(s):  
Michael J. Lopez ◽  
Ai Kondo ◽  
Haruki Nagae ◽  
Koji Yamamoto ◽  
Hayato Tsurugi ◽  
...  
Keyword(s):  
Stereoselective Synthesis ◽  
Internal Alkynes ◽  
Trisubstituted Alkenes

The use of polymer supports in organic synthesis. XII. The total stereoselective synthesis of cis insect sex attractants on solid phases

1977 ◽  
Vol 55 (23) ◽  
pp. 4135-4143 ◽  
Author(s):  
Thomas M. Fyles ◽  
Clifford C. Leznoff ◽  
John Weatherston
Keyword(s):  
Stereoselective Synthesis ◽  
Coupling Reaction ◽  
Ethyl Bromide ◽  
Butyl Bromide ◽  
Sex Attractants ◽  
Polymer Supports ◽  
Acid Cleavage ◽  
Insect Sex Attractants ◽  
Internal Alkynes ◽  
Insect Sex

A 2% crosslinked divinylbenzene-styrene copolymer, incorporating trityl chloride groups (2) was used in the synthesis of insect sex attractants of Lepidoptera by a two-step alkyne coupling route. Polymer 2 reacted with the symmetrical diols, 1,8-octanediol and1,10-decanediol, to give the monoblocked polymer-bound diols 5 and 6 respectively. Mesylation of 5 and 6 gave the polymer-bound monomesylates 7 and 8 which on coupling with lithioacetylide gave the polymer-bound terminal alkynes 9 and 10 respectively. Acid cleavage of 9 and 10 provide 9-decyn-1-ol and 11-dodecyn-1-ol respectively. A second coupling step was performed by lithiation of 9 and 10 with n-butyllithium or tert-butyllithium followed by treatment with n-butyl bromide or ethyl bromide to give polymer-bound internal alkynes, which on acid hydrolysis gave 9-tetradecyn-1-ol (22), 11-hexadecyn-1-ol (23), and 11-tetradecyn-1-ol (24). If 10 had been lithiated with n-butyllithium and coupled with ethyl bromide, some translithiation occurred to liberate n-butyl bromide which entered into the coupling reaction eventually giving a mixture of 23 and 24. This problem was resolved by the use of tert-butyllithium in the lithiation step. Attempts were made to reduce polymer-bound internal alkynes stereoselectively to cis-alkenes with 9-borabicyclononane, diisobutylaluminum hydride, and catechol borane but all these reagents proved inadequate due to incomplete reduction, overreduction, hydrogenolysis of the alkyne from the polymer, and non-selectivity. Polymer-bound internal alkynes were quantitatively reduced exclusively to cis insect sex attractants using disiamylborane without concurrent overreduction or hydrogenolysis.

scholarly journals Regio- and stereoselective multisubstituted olefin synthesis via hydro/carboalumination of alkynes and subsequent iron-catalysed cross-coupling reaction with alkyl halides

2015 ◽  
Vol 2 (9) ◽  
pp. 1053-1058 ◽  
Author(s):  
Shintaro Kawamura ◽  
Ryosuke Agata ◽  
Masaharu Nakamura
Keyword(s):  
Iron Catalyst ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Alkyl Halides ◽  
Synthetic Route ◽  
Olefin Synthesis ◽  
Cross Coupling Reaction ◽  
Direct Cross

A new synthetic route towards multisubstituted olefins was developed based on the direct cross coupling of alkenyl aluminium reagents, prepared by hydro- and carboalumination, with alkyl halides in the presence of an iron catalyst.

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