Synthesis of E-vinyl iodides via Pd-catalyzed hydrostannation of terminal alkynes

Total Synthesis of (+)-Gregatin B and E

“…Since the absolute configuration of the secondary alcohol in the side chain (C5′) was unknown, both enantiomers of the vinyl iodide [( R )- 4a and ( S )- 4a ] were prepared independently (Scheme ). Hydrostannylation of known silyl ether 16 followed by treatment with iodine, and subsequent desilylation, afforded ( R )- 4a and ( S )- 4a in good yields.…”

Linotrins: Omega-3 oxylipins featuring an E,Z,E conjugated triene motif are present in the plant kingdom and alleviate inflammation in LPS-challenged microglial cells

“…Alternatively, the synthesis of (E)-vinyl iodide 6a was achieved via palladium-catalyzed hydrostannation [24,25]. Thus, treatment of the bromoalkyne 22 (readily obtained via silver nitrate mediated-bromination [26]) with Pd(PPh3)4 or Pd2(dba)3/triphenylphosphine catalytic systems in the presence of an excess of tributyltin hydride according to Guibé procedure [27] or tricyclohexylphosphonium tetrafluoborate-Pd2(dba)3-isopropylethyl amine catalyzed [28] hydrostannylation of the terminal alkyne 17, and subsequent in situ iodination showed an excellent (E)-stereoselectivity and good regioselectivity (92 to 95 %), albeit moderate yields (ca. 55%).…”

Metal-Mediated Halogen Exchange in Aryl and Vinyl Halides: A Review

“…In such reactions, alkenyl iodides are usually better reaction partners than their lower homologs, while alkenyl chlorides are more commonly found in natural products and drugs than their brominated and iodinated counterparts. From a synthetic point of view, there are much more methods available for the stereoselective synthesis of alkenyl iodides—which can be readily obtained by iodolysis of vinylmetal species, Takai (Takai et al, 1986 ), or Stork-Zhao (Stork and Zhao, 1989 ) olefinations, hydroiodination of alkynes (Kawaguchi and Ogawa, 2010 ), iododesilylation (Chan and Fleming, 1979 ; Stamos et al, 1996 ; Arefolov et al, 2001 ; Ilardi et al, 2008 ), destannylation (Jung and Light, 1982 ; Darwish and Chong, 2012 ), or Hunsdiecker-type reactions (Das and Roy, 2002 ; Kulbitski et al, 2011 )—than for the synthesis of chlorinated or brominated alkenes. Based on these considerations, being able to efficiently exchange one halogen atom by another one in a stereospecific manner is a fully relevant transformation for which there are now a set of efficient procedures available: they will be reviewed in this section.…”