1402069-83-3Relevant academic research and scientific papers
Stereocontrolled total synthesis of (+)-trans-dihydronarciclasine
Hwang, Soonho,Kim, Deukjoon,Kim, Sanghee
, p. 9977 - 9982 (2012/09/07)
A highly stereoselective and efficient total synthesis of trans-dihydronarciclasine from a readily available chiral starting material was developed. The synthesis defines two of the five stereogenic centers of the natural product by an amino acid ester-enolate Claisen rearrangement. The other three stereogenic centers are created in a highly stereocontrolled fashion via a six-ring vinylogous ester intermediate, which is generated from the γ,δ-unsaturated ester functional group of the Claisen rearrangement product in an efficient three-step sequence. This concise total synthesis exemplifies the use of a highly regioselective Friedel-Crafts-type cyclization to form the B ring via an isocyanate intermediate derived from an N-Boc group, which is superior to the conventional method using an imino triflate intermediate. This same N-Boc group is employed to give high selectivity in the Claisen rearrangement earlier in the sequence. A highly selective and efficient total synthesis of (+)-trans-dihydronarciclasine was developed. The synthesis defines two of the five stereocenters in an amino acid ester-enolate Claisen rearrangement. The other three stereocenters are created via a cyclic vinylogous ester intermediate, which was generated from the γ,δ-unsaturated ester functional group of the rearrangement product. The B ring is constructed by a Friedel-Crafts-type cyclization, exemplifying the use of an N-Boc group to generate an isocyanate intermediate (see scheme). Copyright
