Fluorous Tin Hydrides: A New Family of Reagents for Use and Reuse in Radical Reactions
journal contributionposted on 1999-07-02, 00:00 authored by Dennis P. Curran, Sabine Hadida, Sun-Young Kim, Zhiyong Luo
Eight members of a new family of highly fluorinated (fluorous) tin hydrides have been synthesized and studied as reagents for radical reactions. Tin hydrides of the general formulas [Rf(CH2)n]3SnH and [Rf(CH2)n]Me2SnH have been prepared where Rf is C4F9, C6F13, C8F17, or C10F21 and n is 2 or 3. These reagents are highly soluble in fluorinated solvents, and partition coefficients between perfluorohexanes and several organic solvents have been measured. The reagents are generally useful for reductive radical reactions and hydrostannation reactions that would typically be conducted with tributyltin hydride. Stoichiometric and catalytic procedures have been developed, and both feature very easy separation of the tin products from the organic products by convenient liquid−liquid or solid−liquid extractions. The tin reagents are recovered from reactions in high yields and are routinely reused. Rate constant measurements suggest that the fluorous tin hydrides are about as reactive as (or in some cases, slightly more reactive than) tributyltin hydride. The reagents show excellent potential for large-scale application in “green” (environmentally friendly) processes. In addition, they are useful for combinatorial and parallel synthesis applications both as reagents and as scavengers in phase-switching procedures.