Makoto Kanematsu

Diastereoselective Intramolecular Carbamoylketene/Alkene [2 + 2] Cycloaddition: Enantioselective Access to Pyrrolidinoindoline Alkaloids

A novel and highly diastereoselective intramolecular carbamoylketene/alkene [2 + 2] cycloaddition has been developed, and the methodology was successfully applied to the enantioselective syntheses of (-)-esermethole and Takayamas intermediate for (+)-psychotrimine.

Total synthesis of debromoflustramines B and E based on the intramolecular carbamoylketene-alkene [2 + 2] cycloaddition.

Total synthesis of debromoflustramines B and E has been accomplished by using a platinum-catalyzed addition reaction of o-aminophenylboronic acid with the allene and an intramolecular carbamoylketene-alkene [2 + 2] cycloaddition for the construction of the basic carbon framework of the target alkaloids as the key steps.

SYNTHESIS OF (±)-HELIANNUOL D BASED ON PLATINUM CATALYZED REGIOSELECTIVE ADDITION OF ARYLBORONIC ACIDS TO ALLENES

An alternative total synthesis of (±)-heliannuol D has been achieved in 13 steps and 6.9% overall yield from the arylboronic acid 9. The synthesis applies the previously developed regiocontrolled addition of arylboronic acids to allenes using a platinum catalyst to install the C5 carbon chain on the aryl ring.

Enantioselective Total Syntheses of Pygmaeocins B and C

The first enantioselective total syntheses of pygmaeocins B and C have been accomplished using an efficient and highly diastereoselective intramolecular Heck cyclization for the construction of a quaternary stereogenic center and the functionalized A-ring of the natural products as the key step.

S-15176 and its methylated derivative suppress the CsA-insensitive mitochondrial permeability transition and subsequent cytochrome c release induced by silver ion, and show weak protonophoric activity

A recent report has described that S-15176 (N-[(3,5-di-tert-butyl-4-hydroxy-1-thiophenyl)]-3-propyl-N′-(2,3,4-trimethoxybenzyl) piperazine), an anti-ischemic agent, inhibits the mitochondrial permeability transition (PT) induced by not only Ca2+ and inorganic phosphate, but also by tert-butylhydroperoxide or phenylarsine oxide [Morin et al. (Biochem Pharmacol 72:911–918, 2006)]. In the present study, we tested the effects of S-15176 on the PT induced by Ag+, PT of which is not suppressed by cyclosporin A or oligomycin. S-15176 was effective in suppressing the PT and the subsequent cytochrome c release induced by Ag+, and hence, it was concluded to be a more universal PT inhibitor than cyclosporin A or oligomycin. In addition to the PT-suppression activity, S-15176 also showed weak protonophoric activity. Thus, we further tested to investigate whether the hydroxyl group of S-15176 was involved in its PT-suppression or weak protonophoric activities. The methylated derivative of S-15176 also showed both PT suppression and weak protonophoric activities; hence, the hydroxyl group of S-15176 was concluded not to be involved in these activities.