Recent progress in the synthesis of heterocyclic natural products by the Staudinger/intramolecular aza-Wittig reaction

Abstract

A review of recent progress in the synthesis of heterocyclic natural products by the aza-Wittig method focusing on applications of the tandem Staudinger/intramolecular aza-Wittig reaction.

One-Pot Enantiomeric Synthesis of Thiazole-Containing Amino Acids: Total Synthesis of Venturamides A and B

“…On the basis of our previous studies, we envisaged a tandem phosphine-promoted intramolecular Staudinger-aza-Wittig reaction to form thiazoline intermediate 7 using N-protected amino acids 2 and β-azido disulfides 3 as substrates (Scheme ) followed by a subsequent dehydrogenation of 7 to form the desired chiral TCAA 1 under suitable conditions. It was expected that the mild reaction conditions and the general applicability of Staudinger-aza-Wittig reaction could make this strategy a valuable tool in assembling high enantiomerically enriched TCAAs.…”

Quinoline, quinazoline and acridone alkaloids

“…Eguchi himself has now comprehensively reviewed the process, the versatility of which is demonstrated by the inclusion of many examples illustrating applications in the total synthesis of natural products and various bioactive heterocycles. 105 The procedure, traditionally carried out in solution, has recently been modified to proceed on solid supports, as shown in the synthesis of deoxyvasicinone 209 (= 242, R 1 , R 2 = H; n = 1) and two homologues by Gil and Bräse 106 (Scheme 12). The polymerbound anthranilate 243, which contains a triazene linker, was converted in situ into the acid chloride, which was then coupled with lactams 244 to give the imides 245.…”

Insertion of Isocyanides, Isothiocyanates, and Carbon Monoxide into the Pd−C Bond of Cyclopalladated Complexes Containing Primary Arylalkylamines of Biological and Pharmaceutical Significance. Synthesis of Lactams and Cyclic Amidinium Salts Related to the Isoquinoline, Benzo[g]isoquinoline, and β-Carboline Nuclei

“…The 1,2,3,4-tetrahydroisoquinolin-1-one and 2,3,4,9-tetrahydro-1 H -pyrido[3,4- b ]indol-1-one (tetrahydro-β-carbolinone) rings are structural units found in natural products . Both nuclei possess significant bioactivities (e.g., central nervous system, antiviral, antithrombotic, or cytotoxic activity) and have served as important intermediates for the synthesis of more complex alkaloids and further functionalized polycyclic systems of biological interest. − The wide variety of pharmacological activity associated with cyclic amidines has also been very well documented and includes antitumoral, anticoagulant, antiinflammatory, , antihypertensive, and hypoglycemic activities . In addition, they can act as potent inhibitors of human nitric oxide synthase (NOS) , and glycosidases .…”