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Free keywords:
1,4-selectivity;
asymmetric catalysis;
cascade reactions;
hemiaminals;
metal-free catalysis;
pyrazolidines
Abstract:
Simple yet effective: A highly enantioselective, metal-free cascade reaction between di-1,2-N-protected hydrazine and α,β-unsaturated aldehydes is disclosed. The catalytic, asymmetric cascade transformation is a direct entry to 3-hydroxypyrazolidine and 3-allylpyrazolidine derivatives in one step and two steps, respectively, with >19:1 d.r. and 98–99 % ee using simple chiral pyrrolidines as catalysts.
