A Tin Hydride Designed To Facilitate Removal of Tin Species from Products of Stannane-Mediated Radical Reactions

Abstract

The stannane 1, which is simple to prepare, behaves like the conventional reagents Bu3SnH and Ph3SnH in standard free radical reactions, but with the special characteristic that the tin-containing byproducts are easily and very largely removed by mild hydrolysis (LiOH-water-THF or TsOH-water-THF), which converts them into base-soluble (aqueous NaHCO3) materials. The performance of stannane 1 was evaluated for a range of radical reactions involving halides, selenides, Barton-McCombie deoxygenation, and enyne cyclization. In several cases the effectiveness of the workup procedure in removing tin species was monitored by 1H NMR.

Design, synthesis and in vitro splicing inhibition of desmethyl and carba-derivatives of herboxidiene

“…Treatment of the resulting alcohol with thiocarbonyldiimidazole in toluene at reflux afforded the thiocarbamate in 96% yield. Reduction 32 of the thiocarbamate with tri-n-butyltin hydride in the presence of a catalytic amount of AIBN in toluene at reflux afforded the corresponding deoxygenated product in 74% yield. The resulting diastereomeric mixture was treated with NaH in THF at 23 °C for 4 h furnished a 3:1 mixture of diastereomers.…”

Synthetic approaches to 3H‐naphtho[2,1‐b]pyrans and 2,3‐dihydro‐1H‐naphtho[2,1‐b]pyrans

“…In a publication by Clive and Wang, 2,3-dihydro-1H-naphtho[2,1-b]pyran (40) was prepared in 31% yield by heating 2-allyloxy-1-bromonaphthalene (41) and azobisisobutyronitrile (AIBN) in benzene using a modified stannane reagent (Scheme 12) [34]; the conventional reagent, Bu 3 SnH, gave very poor ($17%) yield [35]. Stannanes such as Bu 3 SnH and Ph 3 SnH are used in standard free radical reactions [35].…”

Radical Cyclizations Leading to the Bicyclo[2.2.1]heptane Framework: A New Radical Approach to (±)-(Z)-β-Santalol

“…Difficulties in removing tin species from the products of stannane-mediated radical reactions are well known. A number of methods has been developed to facilitate product isolation, 14 including fluorous tin reagents in an effort to make organotin chemistry more practical and user friendly. 15 A recent synthesis of gymnomitrene ketone demonstrates the advantage of use of fluorous tin hydrides.…”