{[[K.18-Crown-6]Br3}n: A tribromide catalyst for the catalytic protection of amines and alcohols
作者:Gholamabbas Chehardoli、Mohammad Ali Zolfigol、Fateme Derakhshanpanah
DOI:10.1016/s1872-2067(12)60644-5
日期:2013.9
[K.18-Crown-6]Br3}n, a unique tribromide-type catalyst, was utilized for the N-boc protection of amines and trimethylsilylation (TMS) and tetrahydropyranylation (THP) of alcohols. The method is general for the preparation of N-boc derivatives of aliphatic (acyclic and cyclic) and aromatic, and primary and secondary amines and also various TMS-ethers and THP-ethers. The simple separation of the catalyst
particularly dienylsilylboronates, that are functionalised building blocks in the synthesis of organic and natural products. The mechanism of this new reaction was proved to involve an insertion of alkyne into Ru-H bonds followed by an insertion of coordinated vinyl boronate into the Ru-C= bond and beta-hydrogen transfer to the metal to eliminate boryldiene or borylsilyldiene.
A new efficient route for selective synthesis of various, novel alkynyl(vinyl)substituted silicon (6) and alkynyl[(E)-alkenyl]substituted silicon compounds (9) via silylative coupling of alkynes and their products catalyzed by ruthenium(+2) complexes is described. The tandem procedure facilitates the formation of 9 synthesized in a high yield and stereoselectivity by a sequential silylative coupling
NEW (E)-STYRYL-ALKYNYLSUBSTITUTED SILICON COMPOUNDS AND METHOD OF OBTAINING (E)-STYRYL-ALKYNYLSUBSTITUTED SILICON COMPOUNDS
申请人:Marciniec Bogdan
公开号:US20120178955A1
公开(公告)日:2012-07-12
New (E)-styryl-alkynylsubstituted silicon compounds having the generalized formula 1 and A new method of obtaining (E)-styryl-alkynylsubstituted silicon compounds having the generalized formula 1.
A denotes: phenylmethylsilyl, 1,4-bis(dimethylsilyl)benzene, 1,2-bis(dimethylsilyl)ethane, 1,1,3,3-tetramethyldisilazane, 1,1,3,3-tetramethyldisiloxane, R′ denotes: tri(isopropyl)silyl, 1-pentyl, 2-(trimethylsiloxy)-2-butyl, 1-(trimethylsiloxy)-1-cyclohexyl, triethylgermyl, R′ denotes: H or Cl and when A denotes phenylmethylsilyl then R″ denotes also methyl or a methoxy group. A method of obtaining (E)-styrylalkynylsubstituted silicon compounds having the generalized formula 1 where A, R′ and R″ denote the same as stated above by way of a silylative coupling reaction between a suitable substituted styrene and a suitable vinyl-alkynylsubstituted silicon compound in the presence of a ruthenium(II) complex as catalyst.