An Interesting AlEt₃-Promoted Stereoselective Tandem Rearrangement/Reduction of α-Hydroxy (or Amino) Heterocyclopropane

Abstracts

THF-inactivated AlEt₃ has been found to have an interesting double reactivity: Lewis acidity and reduction activity, which can result in a novel tandem rearrangement/reduction of α-hydroxy (or amino) heterocyclopropane. On the basis of this observation, a facial and highly diastereoselective method for construction of 2-quaternary-1, 3-diheteroatom units has been developed. Three kinds of substrates have been proven to be effective for this reaction.

Key words

triethyl aluminum - Lewis acid - tandem reaction - diols - amino alcohol

References

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3

The general experimental procedure (1a as example): Under Ar protection, a solution (1.0 mL, 3.0 mmol, 3 M) of AlEt₃ in THF, was added dropwise to a stirred solution of 1a (190 mg, 1.0 mmol) in 10 mL dry THF. The reaction mixture was refluxed under Ar atmosphere. After TLC analysis showed the reaction was complete, the reaction mixture was poured into aqueous HCl (2 N) at 0 °C and extracted several times with ether. The combined extracts were dried over Na₂SO₄, concentrated in vacuum and purified on SiO₂ column to give 1b (110 mg, 58%).