218785-22-9Relevant academic research and scientific papers
Total synthesis of (+)-calyculin A and (-)-calyculin B: Cyanotetraene construction, asymmetric synthesis of the C(26-37) oxazole, fragment assembly, and final elaboration
Smith III, Amos B.,Friestad, Gregory K.,Barbosa, Joseph,Bertounesque, Emmanuel,Duan, James J.-W.,Hull, Kenneth G.,Iwashima, Makoto,Qiu, Yuping,Spoors, P. Grant,Salvatore, Brian A.
, p. 10478 - 10486 (2007/10/03)
A convergent total synthesis leading to (+)-calyculin A and (-)-calyculin B (1 and 2), antipodes of the potent, highly selective and remarkably cell-permeable phosphatase inhibitors calyculins A and B, has been achieved. In the preceding paper we outlined the asymmetric synthesis of the C(9-25) spiroketal dipropionate subunit (+)-BC; herein we describe construction of the C(1-8) cyanotetraene, an asymmetric synthesis of the C(26-37) oxazole, fragment assembly and final elaboration to (+)-1 and (-)-2. Highlights of the synthesis include: application of a one-pot three-component Suzuki reaction for the construction of phosphonate A, a bifunctional triene precursor of the light sensitive C(1-8) cyanotetraene subunit, an asymmetric synthesis of the C(26-32) oxazole (-)-D, exploiting the Silks-Odom 77Se NMR protocol to assess enantiomeric purity, construction of the C(33-37) subtarget (-)-E in a highly stereocontrolled fashion via an acyliminium ion, and a concise, highly efficient sequence for fragment assembly and elaboration to (+)-calyculin A and (-)-calyculin B. The synthesis of (-)-2 also confirms the structure of calyculin B, previously based only on spectral comparison with calyculin A.
Stereoselective Synthesis of 2,3-Dihydroxy-4-dimethylamino-5-methoxypentanoic Acid, A Fragment of Calyculins - Determination of the Absolute Configuration of Calyculins
Hamada, Yasumasa,Tanada, Yoshihisa,Yokokawa, Fumiaki,Shiori, Takayuki
, p. 5983 - 5986 (2007/10/02)
2,3-Dihydroxy-4-dimethylamino-5-methoxypentanoic acid (2) with (2R,3R,4R)-configuration has been stereoselectively prepared from (S)-pyroglutaminol (3) and revealed to be the enantiomer of the compound derived from calyculins (1), which provides the conclusicve evidence on the absolutr configuration of calyculins.
