Carbastannatranes: a powerful coupling mediators in Stille coupling

Abstract

Stille coupling is an emerging application of carbastannatranes in organic synthesis because of their excellent tendency to transfer the axial Sn-bound hydrocarbyl substituent. Carbastannatranes have become powerful and versatile cross-coupling mediators in conventionally difficult synthetic routes for producing numerous organic compounds. These reagents belong to the most interesting class of tricyclic compounds, i.e. atranes, which captured the attention of researchers due to the uniqueness of the transannular N/M bond (bonding and variation with axial substituent). Simplicity in synthetic strategies and relatively high stability of carbastannatranes over their analogs (such as organostannanes)is responsible for a wide diversity in conveniently accessible exocyclic substituents. The particular ease of cleaving the axial Sn-C bond (due to the stability of the fused tricyclic skeleton and Sn-C bond activation by the trans-disposed N/Sn bond) made it possible to use carbastannatranes as a reagent in organic and inorganic synthesis. Due to important applications of carbastannatranes in organic synthesis, it is of utmost importance to know these reagents. Thus, a complete coverage of the reports on utilization of carbastannatranes in Stille coupling with various aspects is reported herein to facilitate and motivate the researchers working in this area.

cine- and tele-Substitution reactions: review of work from 2002-2016

“…That was the first example of cine-substitution for imidazo [1,2-a]pyridines. Earlier in this review 9,29,33 it was described that the 3-nitrogroup in trinitroquinolone 67 treated with some carbon nucleophiles such as carbanions from 1,3-dicarbonyls, methyl ketones or neutral enamines could undergo cine-substitution with C-C-bond formation at the position 4. Later, Nishiwaki et al 40 showed that treatment of compound 67 with an excess of aliphatic primary amines could be an effective approach for the formation of the C (4) Unfortunately, cine-substitution of quinolone 67 to afford products 91 was possible only for sterically unhindered amines such as propylamine or isobutylamine.…”

“…In their microreview, Peng and Li 8 focused on the cine-substitution in Stille cross-coupling reactions which often occurred with sterically hindered vinyltin components (over 50 references). Much later Kaur et al in a review 9 on carbastannatranes as mediators in Stille coupling also gave an example of cine-substitution. Ni-catalyzed Suzuki-Miyaura, Fe-catalyzed Kumada cross-coupling reactions of phenol-based electrophiles and other reactions of unconventional phenol derivatives including cine-substituted products were reviewed by Mesganaw and Garg (5 references).…”

Diverse Molecular Architectures of Si and Sn [4.4.3.01,6]Tridecane Cages Derived from a Mannich Base Possessing Semi‐Rigid Unsymmetrical Podands

“…Generally, "atrane-like" cages are comprised of two bridgehead atoms (M and N) connected by identical or different podand arms containing 3 and/or 4 atoms. [18][19][20][21][22] The additional N-M bond provides better chelation to stabilize the transition-metal coordination sphere [17,[23][24][25][26][27][28][29][30][31][32][33][34] and/or main-group metal compounds. [35][36][37] In the past, several main-group compounds and transition-metal complexes containing "atrane-like" structures with unsymmetrical podands and their derivatives have been reported.…”

Organometallic AlaM reagents for umpolung peptide diversification

“…In line with our interest in glycoconjugate synthesis via cross-coupling with anomeric nucleophiles, [64][65][66][67][68] we hypothesized that a stable stannane could be installed at the β carbon in alanine. Tetraalkylstannanes are generally considered poorly nucleophilic, but selective transfer of alkyl groups can be achieved using carbastannatranes [69][70][71][72][73] leading us to propose amino acids with the general formula Ala Sn 11 as competent reagents for umpolung functionalization. Carbastannatranes are significantly less toxic than "normal" stannanes 74 and are compatible with aqueous and buffered conditions.…”