Results Reaction of ethyl propenyl ether, as a 78: 22 cis-trans mixture, with 2 equiv of paraformaldehyde and 2 equiv of Me& at 0" C in CH2Clz (Table I, run 1) gives a 65% yield of an 18: l mixture of threo-and erythro-3-ethoxy-2-methyl-1-butanol (2a) 5 (see eq 2). The relative stereo-erythro 2a chemistry of the isomers of 2a was proven by unambiguous synthesis of both isomers by sodium borohydride reduction of 3-ethoxy-2-methylbutal! ...
