- Lewis acid catalyzed trans-allylsilylation of unactivated alkynes
-
The addition of different substituted allylsilanes 2 to unactivated alkynes 1 in the presence of catalytic mounts of HfCl4 or the EtAlCl2- TMSC1 catalyst system produced in high yields the silylated 1,4-dienes 3 regio- and stereosele
- Yoshikawa, Eiji,Gevorgyan, Vladimir,Asao, Naoki,Yamamoto, Yoshinori
-
-
Read Online
- Regioselective allylgallation of terminal alkynes
-
The reactions of terminal alkynes with allylgallium reagents generated in situ from gallium and allyl bromides gave the corresponding 1,4-dienes in good yield via Markovnikov addition in THF at 70°C. The Royal Society of Chemistry 2005.
- Lee, Phil Ho,Heo, Yunkiu,Seomoon, Dong,Kim, Sundae,Lee, Kooyeon
-
p. 1874 - 1876
(2007/10/03)
-
- Allyl- And Benzylindium Reagents. Carboindation of Carbon-Carbon and Carbon-Nitrogen Triple Bonds
-
The reaction of unactivated simple terminal alkynes 1 with allylindiums in THF proceeded smoothly to give the corresponding allylation products 2 in good to high yields. This result is in marked contrast to that of the reaction carried out in DMF, where the allylation of unactivated alkynes was very sluggish. The allylic group of the reagent was attached to the internal carbon of the triple bond, and indium was attached to the less substituted terminal carbon, except for the case of TMS substituted acetylenes 1j and 1k in which the allyl group went to the less substituted carbon of the triple bond. The reaction of unactivated simple terminal and certain internal acetylenes with benzylindium in THF proceeded smoothly to afford the corresponding benzylation products 18 in good to high yields. The benzyl group was attached to the less substituted unhindered carbon of the triple bond, and indium was attached to the more sterically congested carbon. The reaction of activated nitriles 3 with allylindiums in THF at 70°C gave the corresponding allylationenamination products 4 in high to excellent yields. This reaction provides a useful method for the synthesis of highly functionalized enamines, which are not easily available via conventional methods. The mechanisms on the above three indation reactions are discussed.
- Fujiwara, Naoya,Yamamoto, Yoshinori
-
p. 4095 - 4101
(2007/10/03)
-
- Preparation of 1,4-Dienes from 2-(2-Hydroxyalkylseleno)benzothiazoles by the Reaction Involving Se -> O Azaaromatic Ring Rearrangement
-
The reactions of 2-(2-oxoalkylseleno)benzothiazoles with allylic Grignard reagents in the presence of BF3*OEt2 gave the corresponding 2-benzothiazoles which, on treatment with Ph3P and NaH, afforded 1,4-dienes in good to excellent yields.
- Shibata, Koichi,Mitsunobu, Oyo
-
p. 3163 - 3173
(2007/10/02)
-
- Preparation of 1,4-Dienes from 2-(2-Hydroxyalkylseleno)benzothiazoles by the Reaction involving Se->O Aza-aromatic Ring Rearragement
-
The reaction of 2-(acylmethylseleno)benzothiazoles with allylic Grignard reagents in the presence of BF3*OEt2 gave the corresponding 2-(2-hydroxyalkylseleno)benzothiazoles which, on treatment with NaH and Ph3P, afforded 1,4-dienes in good to excellent yields.
- Shibata, Koichi,Shiono, Hirofumi,Mitsunobu, Oyo
-
p. 661 - 664
(2007/10/02)
-
- ALLYLIC ORGANOBISMETALLIC REAGENTS-PART 2
-
The metalla-Claisen rearrangement of allenyl-allyl zinc reagents described in the preceding letter may follow different patterns according to the nature of the allenyl moiety.It is thus possible to promote three consecutive rearrangements leading to cyclic trismetallic species with good stereoselectivity.
- Normant, J.F.,Quirion, J.Ch.
-
p. 3959 - 3962
(2007/10/02)
-