dc.title: Asymmetric Ru-catalyzed carbonyl allylations via hydrogen transfer to π-unsaturated feedstocks : progress towards the synthesis of bafilomycin A₁ dc.description.abstract: Chemo-, regio-, and enantioselective C–C coupling of alcohols or aldehydes with unsaturated hydrocarbons to furnish chiral homoallylic alcohol products was achieved using iodide-bound ruthenium complexes that are stereogenic at metal and ligand. A ruthenium-JOSIPHOS complex catalyzed the redox-neutral C–C coupling of allene (1,2-propadiene) with primary alcohols to form enantiomerically enriched homoallylic alcohols with complete atom-efficiency. Due to a kinetic preference for primary alcohol dehydrogenation, chemoselective C–C coupling of 1°, 2°–1,3-diols occurs in the absence of protecting groups, enabling concise preparation of previously reported intermediates in the total syntheses of spirastrellolide B, cryptocarya diacetate, and marinomycin A. Divergent regioselectivity in catalytic C–C couplings of isoprene with primary alcohols via hydrogen auto-transfer was observed using ruthenium complexes of the type RuX(CO)[n-prenyl][(S)-SEGPHOS], where X = Cl, I. While the chloride complex promotes sec-prenylation, the pseudo-diastereomeric iodide complex promotes tert-prenylation. Finally, the same iodide-bound ruthenium-SEGPHOS complex was found to catalyze the 2-propanol-mediated reductive coupling of aldehydes with methoxy-allene to form α-methoxy-substituted homoallylic alcohols of good levels of anti-diastereo- and enantioselectivity. The latter method was applied toward synthetic studies of the total synthesis of bafilomycin A₁.