338999-01-2Relevant articles and documents
One-pot synthesis of internal conjugated (Z)-enynyltrimethylsilanes possessing aryl, cycloalkenyl, (E)- or (Z)-alk-l-enyl moieties on the sp carbon atom via two types of cross-coupling reaction
Hoshi, Masayuki,Iizawa, Tomohiko,Okimoto, Mitsuhiro,Shirakawa, Kazuya
experimental part, p. 3591 - 3600 (2009/07/04)
Described herein is an operationally simple and mild method for the stereospecific synthesis of internal conjugated (Z)-enynyltrimethylsilanes whose conjugation is extended away from the distal alkynyl carbon atom. This protocol involves two types of cross-coupling reaction, a Suzuki-type reaction and a sila-Sonogashira reaction, and the desired synthesis can be performed in a one-pot manner. Thus, the copper-mediated cross-coupling reaction of dicyclohexyl[(Z)-1-(trimethylsilyl)alk-l-enyl]boranes with (trimethylsilyl) ethynyl bromide is carried out in the presence of aqueous lithium hydroxide at -15 °C to room temperature, resulting in the stereospecific formation of (Z)-1,3-bis(trimethylsilyl)alk-3-en-1-ynes. Subsequent reaction is allowed to proceed without isolation of the enynes. Thus, palladium/copper-catalyzed cross-coupling reactions with aryl iodides, cycloalk-1-enyl triflates, and (E)- and (Z)-alk-1-enyl iodides can be accomplished in the presence of either 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or tetrabutylammonium fluoride (TBAF) at ambient temperature to provide the corresponding internal conjugated (Z)-enynyltrimethylsilanes possessing one more sp-sp2 carbon bond. Georg Thieme Verlag Stuttgart · New York.
A simple synthesis of B-2-(1-trimethylsilyl-1-alkyl)-1,3,2-dioxaborinanes. Isolation and selective oxidation to 1-trimethylsilyl-1-alkanols
Bhat, Narayan G.,Garza, Amanda
, p. 6833 - 6835 (2007/10/03)
(Z)-1-Trimethylsilyl-1-alkenes easily prepared by the hydroboration of the corresponding 1-trimethylsilyl-1-alkynes followed by protonolysis with acetic acid, readily react with dibromoborane-methyl sulfide complex in dichloromethane for 6 h. The resulting solution is then treated with 1, 3-propane diol in a 1:1 mixture of dichloromethane and n-pentane at 0°C for half an hour to provide the corresponding gem-dimetalloalkanes containing boron and silicon. These alpha-trimethylsilylalkylboronate esters are purified by vacuum distillation in high yields (72-84%) and the structures of these novel intermediates are further confirmed by selective oxidation with alkaline hydrogen peroxide to provide the corresponding alcohols containing trimethylsilyl group.
