Chirospecific synthesis: Catalysis and chiral pool hand in hand

Nature provides us with a wonderful pool of enantiopure starting materials for synthesis: amino acids, sugars, and many (but not all!) terpenes can be isolated even in large quantities in an uncompromised 100 % ee. Vicinal amino alcohols constitute a versatile group of organic structures; they are, in principle, available in enantiopure form from the chiral pool compounds or through chiral catalysis; they are potent intermediates for the synthesis of natural products and medicinally/biologically active compounds, and they provide a highly desirable scaffold for the construction of ligands for metals as well as organocatalysts. These new techniques will open up valuable new possibilities for the invention of new technologies for chemical synthesis, the desired course of chemical discoveries for the future. A robust entry to enantiopure vicinal amino alcohols from inexpensive naturally occurring amino acids has therefore become a key challenge for our endeavors in the development of methodology.Peer reviewe

Conformational control in stereoselective chemical reactions

Funding Information: The results presented in this review are the product of a large number of students in my group over the years. I wish to thank the able students B.Sc. Jane Paul, Ph.D. P?ivi Koskinen, Ph.D. Oili Kallatsa, Ph.D. Mikko Passiniemi, Ph.D. Oskari Karjalainen, and Ph.D. Saara Tiuri for their skilled execution of this research. Skillful technical support for analyses have been provided by P?ivi Joensuu (University of Oulu) and Tiia Sepp? (Aalto University). For NMR experiments, Dr. Jari Koivisto has been instrumental in providing not only help, but also new pulse sequences. Funding for this project has been generously provided by University of Surrey, U.K., Nuffield Foundation, U.K., University of Oulu, Finland, The Finnish Academy, and Aalto University. Networking opportunities through the European collaboration within the COST framework (CM0804, CM1407) is appreciated. Publisher Copyright: © 2021 Japan Institute of Heterocyclic Chemistry. All rights reserved.Two alternative synthetic strategies for the synthesis of vicinal amino alcohols from naturally occurring amino acids have been investigated, viz. one going through diastereoselective addition of organometallic species to an amino aldehyde and one going through α'-chiral α,β-enones and their diastereoselective reduction. Based on these investigations we were able to develop a synthetic strategy towards all diastereomers of deoxynojirimycin starting from naturally occurring serine through a divergent route with a late stage intermediate that can be prepared in large quantities and in enantiomerically pure form.Peer reviewe

Biology and Chemistry of Sphingosine-Related Metabolies

Peer reviewe

A short and efficient synthesis of (2S,3S,4S)-tert-butyl 3,4-dihydroxy-2-(methoxymethyl)-5-oxopyrrolidine-1-carboxylate

Asymmetric synthesis of the title compound was accomplished starting from L-serine. Stannoxane-mediated lactamization provided the key intermediate in good yield.Peer reviewe

Polyketide stereotetrads in natural products

Natural products (or secondary metabolites) remain as the most important source for discovery of new and potential drug molecules. With high resolution data of their structures, and the advancement of synthesis possibilities, analysis of the natural products based on their specific structural features is valuable to those entering the field. In this tutorial review we attempt such an analysis indicating the salient features of the structural classes with examples of the synthesis of each one of them. As the particular class of natural products, we have chosen polyketides.Peer reviewe

Towards the total synthesis of calyculin C: Preparation of the C9-C25 spiroketal-dipropionate unit

An asymmetric synthesis of the C9 –C25 spiroketal fragment of calyculin C is described. Key steps include two crotylation reactions using successively Brown’s reagent and (Z)-crotyltrifluorosilane for the formation of the anti, anti, anti stereotetrad, ynone formation by a Pd-catalyzed coupling of a thiol ester with a terminal alkyne and a double intramolecular hetero-Michael addition for the stereoselective construction of the spiroketal framework.Peer reviewe