Fluorous tin hydrides: A new family of reagents for use and reuse in radical reactions

Eight members of a new family of highly fluorinated (fluorous) tin hydrides have been synthesized and studied as reagents for radical reactions. Tin h ydrides of the general formulas [Rf(CH2)(n)](3)SnH and [Rf(CH2)(n)]Me2SnH h ave 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 bee n measured. The reagents are generally useful for reductive radical reactio ns and hydrostannation reactions that would typically be conducted with tri butyltin hydride. Stoichiometric and catalytic procedures have been develop ed, and both feature very easy separation of the tin products from the orga nic products by convenient liquid-liquid or solid-liquid extractions. The t in reagents are recovered from reactions in high yields and are routinely r eused. Rate constant measurements suggest that the fluorous tin hydrides ar e about as reactive as (or in some cases, slightly more reactive than) trib utyltin hydride. The reagents show excellent potential for large-scale appl ication in "green" (environmentally friendly) processes. In addition, they are useful for combinatorial and parallel synthesis applications both as re agents and as scavengers in phase-switching procedures.