264134-86-3Relevant academic research and scientific papers
First total synthesis of the marine alkaloids (±)-fasicularin and (±)-lepadiformine based on stereocontrolled intramolecular acylnitroso-diels-alder reaction
Abe, Hideki,Aoyagi, Sakae,Kibayashi, Chihiro
, p. 4583 - 4592 (2007/10/03)
The first total synthesis of tricyclic marine alkaloids (±)-fasicularin (2) and (±)-lepadiformine (5) was accomplished. The key common strategic element for the synthesis is the stereocontrolled intramolecular hetero-Diels-Alder reaction of an N-acylnitroso moiety to an exocyclic diene with or without bromine substitution to control the syn-facial or anti-facial selectivity, respectively, leading to the trans- or cis-fused decahydroquinoline ring systems 21 or 39 involving the simultaneous introduction of the nitrogenated quaternary center in a single step. On further elaboration of the six-membered or five-membered ring A, the trans-fused adduct 21 provided either (±)-fasicularin (2) or (±)-lepadiformine (5). The hydrochloride salt of synthetic (±)-5 was found to be identical with the isolated natural sample of lepadiformine; however, the tricyclic amino alcohol 4 having the proposed structure of lepadiformine in a nonzwitterionic form, derived from the cis-fused adduct 39, was found to be different from lepadiformine by spectral comparison. These results thus unambiguously established the relative stereochemistry of lepadiformine, formerly assigned incorrectly, to be 3R*,5S*,7aR*,11aR* shown by 5.
Total synthesis of the proposed structure of lepadiformine via intramolecular N-acylnitroso Diels-Alder reaction
Abe, Hideki,Aoyagi, Sakae,Kibayashi, Chihiro
, p. 1205 - 1208 (2007/10/03)
A stereocontrolled approach to the proposed structure of lepadiformine has been achieved employing an intramolecular hetero Diels-Alder reaction of an N-acylnitroso compound, in which syn-face selectivity was controlled. The NMR data of the product synthesized based on this approach is not identical with those reported for natural lepadiformine. Thus, the proposed structure for natural lepadiformine must be revised. (C) 2000 Elsevier Science Ltd.
