51851-79-7Relevant articles and documents
Tris(pyrazolyl)borate carbosilane dendrimers and metallodendrimers
Camerano, Jose A.,Casado, Miguel A.,Ciriano, Miguel A.,Oro, Luis A.
, p. 5287 - 5293 (2006)
A modified tris(pyrazolylborate) ligand has been prepared in two steps. First, reaction of triisopropylborate with allylmagnesium bromide and further treatment with benzoyl chloride gave CH2 = CHCH2B(O iPr)2 (1), which was then reacted with potassium pyrazolate and pyrazole to give the compound K[CH2 = CHCH 2Bpz3] (2). The new allyl-containing scorpionate anion of 2 acts as a bi- or tri-dentate ligand, as shown by the mononuclear complexes [CH2 = CHCH2Bpz3M(LL)] (M = Rh, LL = nbd, 3; LL = tfb, 4; LL = (CO)(PPh3), 5; M = Ir, LL = cod, 6), obtained from reactions of the chlorido-bridged dinuclear complexes [{M(μ-Cl)(LL)} 2] with 2. Furthermore, the borate 1 represents a key material to achieve the attachment of tris(pyrazolyl)borate groups to the peripheries of carbosilane dendrimers. Thus, the platinum-catalyzed hydrosilylation reactions of compound 1 with the dendritic cores Si[(CH2)3SiMe 2H]4 (G(0)-(SiH)4), (G(1)-(SiH)8), and (G(2)-(SiH)16) gave the corresponding borate-containing dendrimers Si[(CH2)3SiMe2(CH2) 3B(OiPr)2]4 (G(0)-B4), Si[(CH2)3SiMe{(CH2)3SiMe 2(CH2)3B(OiPr)2} 2]4 (G(1)-B8), and Si[(CH2) 3SiMe{(CH2)3SiMe[(CH2) 3SiMe2(CH2)3B(OiPr) 2]2}2]4 (G(2)-B16) selectively in the anti-Markovnikov direction. Further reactions of G(0)-B 4, G(1)-B8 and G(2)-B16 with potassium pyrazolate and pyrazole rendered the corresponding polyanionic dendrimers K 4[Si{(CH2)3SiMe2(CH 2)3Bpz3}4] (G(0)-(Bpz 3)4), G(1)-(Bpz3)8, and G(2)-(Bpz3)16, respectively, which contain 4, 8, and 16 tris(pyrazolyl)borate groups symmetrically located around the dendritic peripheries. These unusual polyanionic dendrimers are excellent scaffolds to support metal centres, as shown by the reactions of G(0)-(Bpz3) 4, G(1)-(Bpz3)8, and G(2)-(Bpz 3)16 with [{Rh(-Cl)(nbd)}2] to give the neutral rhodadendrimers [Si{(CH2)3SiMe2(CH 2)3Bpz3Rh(nbd)}4] G(0)-(Bpz 3Rh)4, G(1)-(Bpz3Rh)8 and G(2)-(Bpz3Rh)16 as stable solids in excellent yields. Following this protocol, mixed rhodium/iridium metallodendrimers can be prepared. The Royal Society of Chemistry 2006.
One-Pot Synthesis of Less Accessible N-Boc-Propargylic Amines through BF3-Catalyzed Alkynylation and Allylation Using Boronic Esters
Yasumoto, Kento,Kano, Taichi,Maruoka, Keiji
supporting information, (2019/05/07)
An efficient synthesis of α-alkynyl- or α-allyl-substituted N-Boc-propargylic amines is described via an alkynylation or allylation of alkynyl-substituted N-Boc-imines. Our strategy relies on the BF3-mediated in situ generation of alkynyl imine
Catalytic enantioselective and catalyst-controlled diastereofacial- selective additions of allyl- and crotylboronates to aldehydes using chiral Bronsted acids
Rauniyar, Vivek,Hall, Dennis G.
, p. 2426 - 2428 (2007/10/03)
(Chemical Equation Presented) Towards the ideal: A chiral diol-SnCl 4 complex is applied to the allylboration of aldehydes (see scheme). This approach highlights the use of chiral Bronsted acid catalysis in the development of an ideal method for the allylation of aldehydes which would display high diastereo- and enantioselectivity, wide substrate scope, and high practicality (ease of use, low cost, and low environmental impact).
