14657-22-8Relevant academic research and scientific papers
Propargylic C(sp3)-H Bond Activation for Preparing η3-Propargyl/Allenyl Complexes of Yttrium
Nagae, Haruki,Kundu, Abhinanda,Tsurugi, Hayato,Mashima, Kazushi
, p. 3061 - 3067 (2017)
Propargylic C(sp3) - H bond activation of 1-substituted-1-propynes, such as 1-trimethylsilyl-1-propyne, 2-hexyne, and 1-phenyl-1-propyne, was achieved by treatment with an alkylyttrium complex 8 bearing an ene-diamido ligand to give the corresponding (η3-propargyl/allenyl)yttrium complexes 7a-c. A unique delocalized η3-propargyl/allenyl structure of these three complexes was revealed by NMR spectroscopy and X-ray single crystal analyses. To elucidate the reactivity of the η3-propargyl/allenyl unit of complexes 7a-c, we conducted two reactions with N-methylaniline and N,N′-dicyclohexylcarbodiimine. For protonation by N-methylaniline, we found that the product distribution of monosubstituted internal alkynes and allenes depended on the substituent on the η3-propargyl/allenyl moiety: 7a and 7b afforded the corresponding internal alkynes as the major products, whereas the major protonation product of 7c was phenylallene. For the insertion of N,N′-dicyclohexylcarbodiimine, complex 7a selectively yielded η3-{N,N′-dicyclohexyl-2-(3-trimethylsilylpropargyl)amidinate}yttrium 12a, while complex 7c produced η3-{N,N′-dicyclohexyl-2-(1-phenylallenyl)amidinate}yttrium complex 13c, though complex 7b gave a mixture of η3-{N,N′-dicyclohexyl-2-(3-normalpropylpropargyl)amidinate}yttrium complex 12b and η3-{N,N′-dicyclohexyl-2-(1-normalpropylallenyl)amidinate}yttrium 13b in an 83:17 ratio. On the basis of the product distributions in these two-types of reactions, (η3-propargyl/allenyl)yttrium complexes were shifted into preferentially favorable η1-allenyl species or η1-propargyl species depending on the substituents prior to the reaction with electrophiles via a four-membered cyclic mechanism.
Preparative synthesis via continuous flow of 4,4,5,5-tetramethyl-2-(3- trimethylsilyl-2-propynyl)-1,3,2-dioxaborolane: A general propargylation reagent
Fandrick, Daniel R.,Roschangar, Frank,Kim, Chunyoung,Hahm, Byoung J.,Cha, Myoung H.,Kim, Hyoun Y.,Yoo, Gyesang,Kim, Taeyun,Reeves, Jonathan T.,Song, Jinhua J.,Tan, Zhulin,Qu, Bo,Haddad, Nizar,Shen, Sherry,Grinberg, Nelu,Lee, Heewon,Yee, Nathan,Senanayake, Chris H.
supporting information; scheme or table, p. 1131 - 1140 (2012/08/13)
A scalable process for the preparation of 4,4,5,5-tetramethyl-2-(3- trimethylsilyl-2-propynyl)-1,3,2-dioxaborolane from trimethylsilylpropyne, isopropyl pinacol borate, and n-butyllithium is described. Problems associated with implementing a typical aqueous workup and batch process into production due to borolane ate equilibration and protonolysis are presented. To address these issues, a continuous-flow and distillation process was developed which efficiently produced 297 kg of the key propargylation reagent.
Regioselective allene synthesis and propargylations with propargyl diethanolamine boronates
Fandrick, Daniel R.,Reeves, Jonathan T.,Tan, Zhulin,Lee, Heewon,Song, Jinhua J.,Yee, Nathan K.,Senanayake, Chris H.
scheme or table, p. 5458 - 5461 (2010/03/01)
"Chemical Equation Presented" The utility of propargyl diethanolamine boronates as reagents for the preparation of allenes and homopropargylic alcohols is presented. Protonolysis with TFA and electrophilic substitution with N-halosuccinimides proceeded wi
Stereoselective synthesis of 2,4,5-trisubstituted tetrahydropyrans using an intramolecular allylation strategy
Jervis, Peter J.,Kariuki, Benson M.,Cox, Liam R.
, p. 4649 - 4652 (2007/10/03)
A highly stereoselective route to 2,4,5-trisubstituted tetrahydropyrans is reported. The key step employs an intramolecular allylation of a (Z)-allylsilane onto an aldehyde under Bronsted acid activation. Complete 1,4-stereoinduction accounts for the form
Using a temporary silicon connection in a highly stereoselective synthesis of a new class of cyclic allenylsilanes
Ramalho, Rui,Beignet, Julien,Humphries, Alexander C.,Cox, Liam R.
, p. 3389 - 3397 (2007/10/03)
Aldehyde 4 reacts in the presence of TMSOTf and an acid scavenger to provide the corresponding oxasilacycle 5 in very good yield and as a single diastereoisomer. The sense of 1,3-stereoinduction serves to introduce a 1,3-syn-diol relationship into the cyc
ALKINE UND CUMULENE-XX. TRIMETHYLSILYLALLENE DURCH RETRO-EN-SPALTUNG VON TRIMETHYLSILYLPROPARGYLETHERN
Hopf, Henning,Naujoks, Elke
, p. 609 - 610 (2007/10/02)
The trimethylsilylallenes 3a-f are obtained in excellent yields when thepropargylic precursors 2a-f are subjected to low pressure flow pyrolysis at ca. 620 deg C.
Gas-Phase Reactions of Anions with Substituted Silanes
DePuy, C. H.,Bierbaum, Veronica M.,Flippin, L. A.,Grabowski, Josef J.,King, Gary K.,et al.
, p. 5012 - 5015 (2007/10/02)
The gas-phase reactions of fluoride, amide, hydroxide, and methoxide ions with a variety of substituted silanes have been studied by the flowing afterglow technique.Fluoride reacts readily with trimethylsilyl derivatives to displace benzyl, alkenyl, and alkynyl anions.These reactions have also been used to generate specific structural isomers (CH3CC- and CH2C=C=CH-).Anions more basic than phenide ion cannot be produced in this manner, and their parent trimethylsilanes interact with fluoride by more complex mechanisms.Amide, hydroxide, and methoxide ions react with substituted trimethylsilanes by both displacement and proton abstraction whenever an acidic hydrogen is present; in the absence of displaceable groups and acidic hydrogen, the reactions of amide, hydroxide, and methoxide parallel those of fluoride ion.
