During recent years, the direct transformation of aldehydes into esters or amides has developed into a vigorous research area and powerful one-pot oxidative esterification and amidation procedures have been reported. Several concepts that are often complementary in substrate scope, functional group tolerance, and reaction outcome have emerged, thus providing a wide range of alternatives to classical ester and amide synthesis via carboxylic acid intermediates.

One‐Pot Oxidative Esterification and Amidation of Aldehydes

A comprehensive overview of the taiwaniaquinoid family of natural products is presented. A summary of the isolation, biosynthesis, and biological activity of these compounds is followed by a discussion of various synthetic strategies to the skeletal framework and a detailed discussion of 12 published syntheses of members of this family. This review covers the literature from the discovery of the first taiwaniaquinoid in 1995 until June 2009.

The taiwaniaquinoids: a review.

ConspectusChemists no longer doubt the importance of a methodology that could activate and utilize aldehydes in organic syntheses since many products prepared from them support our daily life. Tremendous effort has been devoted to the development of these methods using main-group elements and transition metals. Thus, many organic chemists have used an activator–(aldehyde oxygen) interaction, namely, η1 coordination, whereby a Lewis or Bronsted acid activates an aldehyde. In the field of coordination chemistry, η2 coordination of aldehydes to transition metals by coordination of a carbon–oxygen double bond has been well-studied; this activation mode, however, is rarely found in transition-metal catalysis. In view of the distinctive reactivity of an η2-aldehyde complex, unprecedented reactions via this intermediate are a distinct possibility.In this Account, we summarize our recent results dealing with nickel(0)-catalyzed transformations of aldehydes via η2-aldehyde nickel and oxanickelacycle intermediates....

Catalytic Transformation of Aldehydes with Nickel Complexes through η2 Coordination and Oxidative Cyclization

The frondosins are a family of marine sesquiterpenes isolated from the sponge Dysidea frondosa that exhibit biological activities ranging from anti-inflammatory properties to potential application in anticancer and HIV therapy. Herein, a concise enantioselective total synthesis of (+)-frondosin B is described which requires a total of three chemical steps. The enantioselective conjugate addition of a benzofuran-derived boronic acid to crotonaldehyde in the presence of an imidazolidinone organocatalyst builds the critical stereogenic center of frondosin B in the first operation, while the remaining two ring systems of this natural product are installed in the two subsequent steps. A combination of X-ray crystallographic data, deuterium labeling, and chemical correlation studies provides further evidence as to the correct absolute stereochemical assignment of (+)-frondosin B.

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The organocatalytic three-step total synthesis of (+)-frondosin B

The first synthesis of the biologically active humulene natural product asteriscunolide D has been accomplished in nine steps without the use of protecting groups. The challenging 11-membered ring was forged via a diastereoselective thionium ion initiated cyclization, which constitutes a formal aldol disconnection to form a strained macrocycle. A stereospecific thioether activation-elimination protocol was developed for selective E-olefin formation, thus providing access to the most biologically active asteriscunolide. The absolute stereochemical configuration was established by the Zn-ProPhenol catalyzed enantioselective addition of methyl propiolate to an aliphatic aldehyde to afford a γ-hydroxy propiolate as a handle for butenolide formation via Ru-catalyzed alkene-alkyne coupling.

/pdf/thionium-ion-initiated-medium-sized-ring-formation-the-total-4c5tqi8czw.pdf

Thionium Ion Initiated Medium-Sized Ring Formation: The Total Synthesis of Asteriscunolide D

https://research.aalto.fi/files/7157259/A_short_and_convenient_way_to_produce_the_Taxol_A_.pdf

A short and convenient way to produce the Taxol A-ring utilizing the Shapiro reaction

http://lib.tkk.fi/Diss/2002/isbn9512259133/article2.pdf

Selective Mixed Tishchenko Reaction via Substituted 1,3-Dioxan-4-ols

http://lib.tkk.fi/Diss/2002/isbn9512259133/article3.pdf

Monoalcoholates of 1,3-diols as effective catalysts in the Tishchenko esterification of 1,3-dioxan-4-ols

http://lib.tkk.fi/Diss/2002/isbn9512259133/article4.pdf

Olli P. Törmäkangas

Papers

A short and convenient way to produce the Taxol A-ring utilizing the Shapiro reaction

Selective Mixed Tishchenko Reaction via Substituted 1,3-Dioxan-4-ols

Monoalcoholates of 1,3-diols as effective catalysts in the Tishchenko esterification of 1,3-dioxan-4-ols

Fast Aldol-Tishchenko Reaction Utilizing 1,3-Diol Monoalcoholates as the Catalysts

The Tischenko Reaction and its Modifications in Organic Synthesis