1,2-Aminoalcohols, from oxiranes

The effect of a heteroatom 0 to the oxirane ring has been studied in the reaction of monosubstituted oxiranes 131 and benzylamine. If X = 0, the reaction occurs via the transition state 132 with neighbouring-group participation. Neighboring-group participation has similarly been observed in the reactions of mono- and tri-substituted oxiranes and )3-substituted primary amines. The product ratio of the aminoalcohols formed from the reactions of a-vinyloxiranes and primary amines depends on the geometry of the oxirane.Base-catalyzed addition of oxiranes to oximes leads not only to 0-alkyl but to A -alkyl derivatives (Eq, 319). ... 

In contrast to HFPO, 2,2-bis(trifluoromethyl)oxirane (2) ring opens with oxygen, nitrogen, sulfur, and carbon nucleophiles at the less hindered carbon, yielding tertiary alcoholsWith diethylamine, for example, 2 affords an aminoalcohol in 83% yield. Oxirane 2 played an important role in the development of monomers from which to build highly transparent, yet readily alkali-soluble photoresist copolymers... 

The synthesis of the enantiopure AB segment 184 [68] by Shibasaki et al. [178] relied on the enantioselective opening of the oxirane ring of the readily available meso-epoxide 177 with p-anisidine [179,180], followed by two steps with 1,3-chiraUty transfer. After extensive experimentation the best enantiomeric excess was obtained with a catalyst prepared from Pr(0-f-Pr)3-(Jl)-BINAP in the ratio 1 1.5 with three equivalents of triph-enylphosphine oxide as an additive. Thus, reaction of 177 with p-anisidine in the presence of 10 mol% of the chiral catalyst provided fraws-aminoalcohol 178 in 80% yield with a moderate enantiomeric excess (65% ee), which was raised to 95% ee by one recrystaUization in 40% yield (Scheme 36). Methy-lation of 178 and Hofmann degradation of the resulting quaternary salt with butyllithium at -78 °C gave aUyhc alcohol 179. Oxymercuration of alcohol 179 with Hg(OAc)2 in methanol, followed by sodium borohydride reduction [181]... 

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