Rearrangements of organosilicon compounds using organoaluminum reagents. Conversion of phenyl- and alkenyl(chloromethyl)silanes to benzyl- and allylsilanes
摘要:
Various (chloromethyl)silanes undergo Wagner-Meerwein-type rearrangements using a catalytic amount of EtAlCl2 in dichloromethane. The resulting chlorosilanes have been converted to alkyl(or aryl)silanes with RMgX and/or to fluorosilanes with NH4BF2. In this way phenyl-, alkenyl-, and allyl(chloromethyl)silanes were converted to benzyl-, allyl-, and homoallylsilanes, respectively. Attempted rearrangements of methyl-, alkynyl-, and furyl(chloromethyl)silanes under these conditions were not successful.
Stereospecific Iron-Catalyzed Carbon(sp<sup>2</sup>)–Carbon(sp<sup>3</sup>) Cross-Coupling with Alkyllithium and Alkenyl Iodides
作者:Xiao-Lin Lu、Mark Shannon、Xiao-Shui Peng、Henry N. C. Wong
DOI:10.1021/acs.orglett.9b00394
日期:2019.4.19
An efficient synthetic protocol involving iron-catalyzed cross-coupling reactions between organolithium compounds and alkenyl iodides as key coupling partners was achieved. More than 30 examples were obtained with moderate to good yields and high stereospecificity. Gram-scale and synthetic applications of this procedure are recorded herein to demonstrate its feasibility and potential utilization.
Stereoselective Negishi-like Couplings Between Alkenyl and Alkyl Halides in Water at Room Temperature
作者:Arkady Krasovskiy、Christophe Duplais、Bruce H. Lipshutz
DOI:10.1021/ol101885t
日期:2010.11.5
Mix in water and then stir. That is all that is required in this new approach to stereoselective sp3−sp2 cross-couplings between an alkyl and alkenyl halide. Prior formation of organozinc reagents is not required.
Reaction of 1-(chloromethyldimethylsilyl)-1-alkyne with triisobutylaluminium gives 2-(isobutyldimethylsilyl)-1-alkene exclusively. Reactions of the lithiated allylsilane with several electrophiles give the corresponding carbometallated products, allylsilanes bearing alkyl, allyl, vinyl, or alkoxycarbonyl groups. Protodesilylation of 3-(trimethylsilylmethyl)-1,3-decadiene gives 3-methylene-1-decene selectively
A simple synthesis of allylsilanes via tris[(trimethylsilyl)methyl]borane
作者:Kung K Wang、Sujitra Dhumrongvaraporn
DOI:10.1016/s0040-4039(00)95897-0
日期:1987.1
Allylsilanes were prepared by protonation or alkylation of lithium 1-alkynyltris[(trimethylsilyl)methyl]borates followed by protonolysis or treatment with aqueous sodium hydroxide and iodine.
Regio- and stereoselective hydralumination of 1-chloromethyldimethylsilyl-1-alkyne with DIBAH affords (Z)-1- chloromethyldimethylsilyl-1-diisobutylalumino-1-alkene which gives (E)-1-trimethylsilyl-2-alkene as a sole product by successive treatment with 3 equiv of methyllithium and water. Reaction of the organoaluminium intermediate with trimethyl-aluminium in refluxing heptane produces a mixture of