A Highly Atom Efficient, Solvent Promoted Addition of Tetraallylic, Tetraallenic, and Tetrapropargylic Stannanes to Carbonyl Compounds
摘要:
Tetraallylic, tetraallenic, and tetrapropargylic stannanes (0.25 equiv) react with aldehydes in methanol to provide unsaturated alcohols in good to excellent yields (56-99%). These reactions proceed exclusively with allylic rearrangement for tetra(2-butenyl)tin 2b and tetra(1,2-butadienyl)tin 16c and predominantly with allylic rearrangement for tetrapropadienyltin 16a and tetra(2-butynyl)tin 6e. Allylation. reactions also proceeded smoothly with reactive ketones such as ethyl pyruvate (9a) and cyclohexanone (9b). The corresponding TFA-catalyzed reactions of dimethyl acetals 4d and 4e are regiospecific with allylic rearrangement.
A novel mode of access to polyfunctional organotin compounds and their reactivity in Stille cross-coupling reaction
摘要:
Mono-, di-, tri- and tetra-functional organotin compounds were easily prepared in a sonicated Barbier reaction using ultrasound technology via coupling reaction of organo halides with tin halides (Bu3SnCl, Bu2SnCl2, BuSnCl3, SnCl4) mediated by magnesium metal. The di- and tri- functional organotin compounds were tested in a Stille cross-coupling reaction in order to ascertain how many groups were transferred. (C) 2009 Elsevier B.V. All rights reserved.