1-alkoxyallene as an effective precursor for regio- and stereocontrolled allylation reactions with aliphatic aldehydes via bis-stannylation

Bis-stannylation of 1-(methoxy)methoxyallene yields (E)-(3-(methoxymethoxy)prop-2-ene-1,2-diyl) bis-tributylstannane (2) as a highly reactive allylation reagent. Stereoselective reactions of functionalized stannane 2 with a variety of aldehydes provide good yields of 1,2-diol derivatives. Reactions with alpha-alkoxyaldehydes proceed with chelation-controlled addition to afford efficient constructions of 3,4-anti-4,5-syn-relationships in stereotriads bearing three differentiated oxygen (alkoxy and hydroxy) substituents. Mechanistic considerations are presented, and derivatives for NMR experiments support the stereochemical assignments. An X-ray diffraction study is included.