Synthesis of 3-Fluoropyrrolidines and 4-Fluoropyrrolidin-2-ones from Allylic Fluorides
作者:Lorraine E. Combettes、Marie Schuler、Rakesh Patel、Baltasar Bonillo、Barbara Odell、Amber L. Thompson、Tim D. W. Claridge、Véronique Gouverneur
DOI:10.1002/chem.201201576
日期:2012.10.8
were prepared by 5‐exo‐trig iodocyclisation fromallylicfluorides bearing a pending nitrogen nucleophile. These bench‐stable precursors were made accessible upon electrophilic fluorination of the corresponding allylsilanes. The presence of the allylic fluorine substituent induces syn‐stereocontrol upon iodocyclisation with diastereomeric ratios ranging from 10:1 to > 20:1 for all N‐tosyl‐3‐fluoropent‐4‐en‐1‐amines
A Nazarov‐Ene Tandem Reaction for the Stereoselective Construction of Spiro Compounds
作者:Christoph Etling、Giada Tedesco、Markus Kalesse
DOI:10.1002/chem.202101041
日期:2021.6.25
cyclization tandem reaction is presented, terminating the oxyallyl cation by an ene-type reaction, and leading stereoselectively to bicyclic spiro compounds. The terminal olefin of this motif represents a useful handle for further functionalization, making it a strategic intermediate in total syntheses. The tandem Nazarov/ene cyclization was shown to be preferred over a Nazarov/[3+2] tandem reaction for all our
Preparation of (
<i>Z</i>
)‐Alk‐2‐ene‐1,5‐diols by the Titanocene(II)‐Promoted Cyclization of Thioacetals Possessing a Terminal Carbon−Carbon Double Bond
Titanocene(II)-promoted ring-closing metathesis of the titanium carbene complexes prepared from [2,2-bis(phenylthio)ethyl](but-3-enyloxy)dimethylsilanes or dimethyl(prop-2-enyl)silyl ethers of 3,3-bis(phenythio)propanols gave seven-membered cyclic unsaturated silyl ethers. Oxidative cleavage of a silicon−carbon bond of the cyclic silyl ethers resulted in olefinic diols, with high Z stereoselectivity.
Lewis Acid-Catalyzed Friedel−Crafts Alkylation of Ferrocene with Allylchlorosilanes
作者:Samyoung Ahn、Young-Sang Song、Bok Ryul Yoo、Il Nam Jung
DOI:10.1021/om0000865
日期:2000.7.1
Friedel−Crafts alkylations of ferrocene, 1, with allylchlorosilanes in the presence of Lewis acid catalysts under mild conditions gave regiospecific [1-methyl-2-(alkylchlorosilyl)ethyl]ferrocenes in fair to good yields depending upon the substituents on silicon, along with small amounts of dialkylated products. The alkylation of ferrocene with 1.2 equiv of (2-methylallyl)dimethylchlorosilane, 2b, at
Diastereoselective synthesis of trisubstituted olefins using a silicon-tether ring-closing metathesis strategy
作者:Stéphane Wittmann、Alexander F. Tiniakos、Joëlle Prunet
DOI:10.1039/c9ob02563d
日期:——
trisubstituted olefins with concomitant C–C bond formation is still a difficult challenge, and olefinmetathesis reactions for the formation of such alkenes are usually not high yielding or/and diastereoselective. Herein we report an efficient and diastereoselective synthesis of trisubstituted olefins flanked by an allylic alcohol, by a silicon-tether ring-closing metathesisstrategy. Both E- and Z-trisubstituted