88754-00-1Relevant academic research and scientific papers
A Regioselective and Stereospecific Synthesis of Allylsilanes from Secondary Allylic Alcohol Derivatives
Fleming, Ian,Higgins, Dick,Lawrence, Nicholas J.,Thomas, Andrew P.
, p. 3331 - 3350 (2007/10/02)
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 th e 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 stereochemically complementary, the former being stereospecifically anti and the latter stereospecifically syn.Homochiral allylsilanes can be ma de by these methods with high levels of stereospecificity, as shown by the synthesis of the allylsilanes 54, 58 and 59.
The Stereochemistry of the Silyl-cupration of Allenes
Fleming, Ian,Landais, Yannick,Raithby, Paul R.
, p. 715 - 719 (2007/10/02)
The silyl-cupration of the stereochemically defined allenes 6 and 7 is stereospecifically syn, giving the allylsilanes 8 and 9, respectively
A Stereospecific Synthesis of Optically Active Allylsilanes
Fleming, Ian,Thomas, Andrew P.
, p. 1456 - 1457 (2007/10/02)
The phenyldimethylsilyl-cuprate reagent reacts with secondary allyl acetates stereospecifically anti, and with secondary and tertiary allyl urethanes stereospecifically syn; these reactions can be used to synthesise either enantiomer of an optically activ
STEREOSPECIFIC SYNTHESES AND REACTIONS OF ALLYL- AND ALLENYL-SILANES
Fleming, Ian,Terrett, Nicholas K.
, p. 99 - 118 (2007/10/02)
The stereospecifically anti synthesis of allyl- and allenyl-silanes by the reaction of a silylcuprate reagent with allyl and propargyl acetates is described.The SE2' reactions of these silanes with various electrophiles are shown to proceed wit
STEREOSPECIFICITY IN THE SYNTHESIS OF ALLYLSILANES FROM TERTIARY ALLYLIC ACETATES
Fleming, Ian,Terrett, Nicholas K.
, p. 4151 - 4152 (2007/10/02)
The tertiary allylic acetates (1-4) and the propargylic acetates (14 and 15) react with our silyl-cuprate reagent (5) to give, in a cleanly anti manner, the stereodefined allylsilanes (6 and 7) and allenylsilanes (16 and 17).
