Journal ArticleDOI
A regioselective and stereospecific synthesis of allylsilanes from secondary allylic alcohol derivatives
Reads0
Chats0
TLDR
In this paper, the reaction of the silyl-cuprate with allylic esters and the three-step sequence with the carbamates is stereo-chemically complementary.Abstract:
Primary and secondary allylic acetates and benzoates react with the dimethyl (phenyl)silyl-cuprate reagent to give allylsilanes, provided that the THF in which the cuprate is prepared is diluted with ether before addition of the allylic ester. The reaction is reasonably regioselective in some cases: (i) when the allylic system is more-substituted at one end than the other, as in the reactions 4→5 and 9→10; (ii) when the steric hindrance at one end is neopentyl-like, as in the reactions 15→16; and (iii) when the disubstituted double bond has the Z configuration, as in the reactions Z-19→E-21 or, better, because the silyl group is becoming attached to the less-sterically hindered end of the allylic system, Z-20→E-22. The regioselectivity is better if a phenyl carbamate is used in place of the ester, and a three-step protocol assembling the mixed cuprate on the leaving group is used, as in the reactions 23→24 and E- or Z-29→E-21, or, best of all, because the silyl group is again becoming attached to the less-sterically hindered end of the allylic system, E- or Z-30→E-22. This sequence works well to move the silyl group onto the more substituted end of an allyl system, but only when the move is from a secondary allylic carbamate to a tertiary allylsilane, as in the reaction 38→39. Allyl(trimethyl)silanes can be made using alkyl- or aryl-cuprates on trimethylsilyl-containing allylic esters and carbamates, as in the reactions 40→41, and 43→44. The reaction of the silyl-cuprate with allylic esters and the three-step sequence with the allylic carbamates are stereo-chemically complementary, the former being stereospecifically anti and the latter stereospecifically syn. Homochiral allylsilanes can be made by these methods with high levels of stereospecificity, as shown by the synthesis of the allylsilanes 54, 58 and 59.read more
Citations
More filters
Journal ArticleDOI
Stereochemical Control in Organic-Synthesis Using Silicon-Containing Compounds
Journal ArticleDOI
An Extremely Powerful Acylation Reaction of Alcohols with Acid Anhydrides Catalyzed by Trimethylsilyl Trifluoromethanesulfonate
TL;DR: Trimethylsilyl trifluoromethanesulfonate is an excellent catalyst for the acylation of alcohols with acid anhydrides and was used in this paper.
Journal ArticleDOI
Directed Reactions of Organocopper Reagents
Bernhard Breit,Yvonne Schmidt +1 more
TL;DR: Chiral Reagent-Directing Groups 2944 3.5.1.
Journal ArticleDOI
Silylation of Allylic Trifluoroacetates and Acetates Using Organodisilanes Catalyzed by Palladium Complex
Yasushi Tsuji,Masahiro Funato,Masakatsu Ozawa,Hiroaki Ogiyama,Satoshi Kajita,Takashi Kawamura +5 more
TL;DR: In this article, the silylation of allylic acetates (1) using organodisilanes (2) was carried out in the presence of a catalytic amount of Pd(DBA)2−LiCl at 100 °C.
Journal ArticleDOI
Silicon‐ and Tin‐Based Cuprates: Now Catalytic in Copper!
TL;DR: These efforts towards copper(I)-catalyzed carbon--silicon and also carbon--tin bond formations are described using soft bis(triorganosilyl) and bis( triorganostannyl) zinc reagents as powerful sources of nucleophilic silicon and tin.
References
More filters
Journal ArticleDOI
.alpha.-Methoxy-.alpha.-trifluoromethylphenylacetic acid, a versatile reagent for the determination of enantiomeric composition of alcohols and amines
Journal ArticleDOI
Lanthanoids in organic synthesis. 6. Reduction of .alpha.-enones by sodium borohydride in the presence of lanthanoid chlorides: synthetic and mechanistic aspects
Andre L. Gemal,Jean Louis Luche +1 more
Journal ArticleDOI
Nucleophilic and organometallic displacement reactions of allylic compounds: stereo-and regiochemistry
TL;DR: In this paper, stereo and regiochemical aspects of three reaction types: the SN2' reaction (bimolecular nucleophilic substitution with allylic rearrangement); displacement reactions effected by organometallic reagents; the conversion of allylic alcohols into halides.
Journal ArticleDOI
Optically active allylsilanes. 1. preparation by palladium-catalyzed asymmetric grignard cross-coupling and anti stereochemistry in electrophilic substitution reactions
Related Papers (5)
Diastereoselective Reactions of Chiral Allyl and Allenyl Silanes with Activated C:X .pi.-Bonds
Craig E. Masse,James S. Panek +1 more