Polyketide construction via hydrohydroxyalkylation and related alcohol C-H functionalizations: reinventing the chemistry of carbonyl addition.

Despite the longstanding importance of polyketide natural products in human medicine, nearly all commercial polyketide-based drugs are prepared through fermentation or semi-synthesis. The paucity of manufacturing routes involving de novo chemical synthesis reflects the inability of current methods to concisely address the preparation of these complex structures. Direct alcohol C-H bond functionalization via"C-C bond forming transfer hydrogenation" provides a powerful, new means of constructing type I polyketides that bypasses stoichiometric use of chiral auxiliaries, premetallated C-nucleophiles, and discrete alcohol-to-aldehyde redox reactions.

Asymmetric alcohol C-H allylation and syn-crotylation: C9-C20 of tetrafibricin.

The C9-C20 segment of the fibrinogen receptor inhibitor tetrafibricin was prepared in 10 steps (longest linear sequence). Ruthenium catalyzed enantioselective syn-crotylation is used to construct C9-C13. Iridium catalyzed asymmetric alcohol C-H allylation of a commercial malic acid derived alcohol is used to construct C14-C20.

[Anesthetic management for gastrectomy in two gastric cancer patients after coronary artery bypass grafting using right gastroepiploic artery].

We report two cases for anesthetic management of gastrectomy for gastric cancer which took place after receiving coronary artery bypass grafting (CABG) using the right gastroepiploic artery (RGEA). The first patient was a 75-year-old man after CABG using the RGEA 14 years before. He was diagnosed with gastric cancer and was scheduled for total gastrectomy.

Asymmetric aldol reaction of acetaldehyde and isatin derivatives for the total syntheses of ent-convolutamydine E and CPC-1 and a half fragment of madindoline A and B.

The asymmetric aldol reaction of isatin derivatives and acetaldehyde has been developed using 4-hydroxydiarylprolinol as a catalyst, affording the aldol products with high enantioselectivity, these products being key intermediates in the synthesis of 3-hydroxyindole alkaloids. Short syntheses of ent-convolutamydine E and CPC-1 and a half fragment of madindoline A and B have been accomplished.

Asymmetric, catalytic, and direct self-aldol reaction of acetaldehyde catalyzed by diarylprolinol.

An asymmetric, catalytic, and direct self-aldol reaction of acetaldehyde was catalyzed by diarylprolinol in NMP, affording the trimer acetal, which was generated by the reaction of the self-aldol product with another acetaldehyde molecule in a moderate yield with good enantioselectivity. Acetal is the synthetic equivalent of the self-aldol product, which can be converted into other synthetically useful compounds in one pot without compromising the enantioselectivity.

Highly diastereo- and enantioselective direct aldol reactions of aldehydes and ketones catalyzed by siloxyproline in the presence of water.

Proline-based organocatalysts have been developed for a highly enantioselective, direct aldol reaction of aldehydes and ketones in the presence of water. While several surfactant-proline combined catalysts have proved effective, proline derivatives with a hydrophobic moiety such as trans-siloxy-L-proline and cis-siloxy-D-proline, both of which are easily prepared from the same commercially available 4-hydroxy-L-proline, have been found to be the most effective organocatalysts examined in this study, affording the aldol product with excellent diastereo- and enantioselectivities, these two catalysts generating opposite enantiomers. Water affects the selectivity, and poor results are obtained under neat reaction conditions or in dry organic solvents.

Small organic molecule in enantioselective, direct aldol reaction "in water".

A small organic molecule, Pro-NH(2), catalyzing the enantioselective aldol reaction "in water" not merely "in the presence of water" with good enantioselectivity has been discovered for the first time.

Differentiation between intradural and extradural locations of juxta-dural ring aneurysms by using contrast-enhanced 3-dimensional time-of-flight magnetic resonance angiography.

Background: Juxta-dural ring aneurysms of the ICA have different clinical outcomes and risks for SAH, which are dependent on their position in the intradural or extradural space. The aim of this study was to reveal the precise location of such aneurysms by using CE-MRA.

Methods: Contrast-enhanced MRA studies were performed in 21 patients with 24 juxta-dural ring aneurysms.

Dry and wet prolines for asymmetric organic solvent-free aldehyde-aldehyde and aldehyde-ketone aldol reactions.

Dry and wet prolines were found to catalyze the direct aldol reactions of aldehyde-aldehyde and aldehyde-ketone, respectively, to afford aldols with excellent diastereo- and enantioselectivities, and an organic solvent-free reaction was realized in some cases.