A Convergent Total Synthesis of Balticolid.

A convergent total synthesis of the 12 membered macrolide, Balticolid (1) is described, starting from readily available homoallylic alcohol and 1,3 propane diol The synthetic strategy involves the construction of the 12-membered lactone.

Bismuth(III) salts as synthetic tools in organic transformations.

Bismuth is the heaviest stable element of the periodic table and even though it carries the status of heavy metal, it is rated as relatively nontoxic and noncarcinogenic unlike its neighboring elements. Additionally, the fact that it tolerates air and moisture makes the chemistry of bismuth attractive to synthetic chemists. The catalytic nature of this metal is attributed to the capability of its salts to acts as Lewis acids in reactions. The nontoxicity together with the ability to endure moisture makes bismuth compounds favorites of chemists and scientists who are concerned about environmental hazards, and such properties are highly desirable for scale-up of a method. The Lewis acidic nature of salts of this element have been thoroughly investigated in various types of reactions such as cycloaddition reactions, reactions of sugars, protection and deprotection reactions, synthesis of heterocyclic systems etc. Since the 1990s, various research groups have successfully utilized this catalytic nature for many organic transformations. Our group's contribution towards the development of methodologies that are useful in accomplishing various functional group manipulations by making use of the catalytic properties of bismuth salts is portrayed here. The mechanistic aspects and the catalytic efficiency of the bismuth(III) salts are accented together with the synthetic utility and the biological and pharmacological applications of the methodologies developed.

Versatile intramolecular aza-Prins and Prins cyclization of aryl epoxides: a facile synthesis of diaza-, oxa-aza-, and dioxa-bicycles.

Aryl epoxides undergo coupling smoothly with (E)-hex-3-ene-1,6-ditosylamide in the presence of 10 mol % p-TSA in 1,2-dichloroethane at 75 degrees C to produce the corresponding 1,5-ditosyl-octahydro-1H-pyrrolidino[3,2-c]pyridines in good yields with high trans-selectivity, whereas the coupling of (Z)-hex-3-ene-1,6-ditosylamide gave cis-fused octahydro-1H-pyrrolidino[3,2-c]pyridines predominantly. The use of readily available p-TSA makes this method simple, convenient, and practical.

Gold(III) chloride-catalyzed three-component reaction: a facile synthesis of alkynyl derivatives of 1,2-dihydroquinolines and isoquinolines.

Gold(III) chloride is found to be an effective catalyst for the addition of alkynes on activated quinoline/isoquinolines to produce a series of alkynyl-substituted 1,2-dihydroquinolines and isoquinolines in a single-step operation. The easy availability of starting materials, convenient synthetic procedure, operational simplicity, and high regioselectivity makes this strategy very useful for the preparation of enyne derivatives of aza-aromatic compounds.

Three-component reaction of aldose sugars, aryl amines, and 1,3-diones: a novel synthesis of annulated pyrroles.

Aldose sugars undergo smooth coupling with enamines, generated in situ from aryl amines and 1,3-diketones, in the presence of 10 mol % of InCl3 in water at 80 degrees C to furnish annulated pyrrole derivatives in relatively good to high yields. The use of InCl3, in combination with water, makes this procedure quite simple, more convenient, and environmentally friendly.