A Stereoselective Synthesis of Nonracemic (+)-Desoxoprosophylline by a Tandem Wittig [2+3]-Cycloaddition Reaction

Abstract

L‐Ascorbic acid serves as chiral starting material for the synthesis of (+)‐desoxoprosophylline. The synthetic pathway includes the formation of an O‐protected 5‐azido‐2,3‐dideoxysugar which is subjected to a tandem Wittig [2+3]‐cycloaddition reaction, leading to the heterocyclic core unit of (+)‐prosophylline. Stereoselective hydrogenation and chain elongation yields the desired alkaloid.

Intrinsic Organic‐Based Synthetic/Artificial Antiferromagnets

“…The method presented herein provides a new rapid access to various enantiopure pyrrolidine vinylogous amides in good yields. Such compounds, which can be prepared by Eschenmoser coupling17 or Knoevenagel‐type reactions,18 have been used as intermediates in the synthesis of many natural compounds,19 such as anisomycin,20a apomitomycin,20b mesembrenone,20c desoxoprosophylline,20d cassine,19c pinidinone,20e deoxyfebrifugine,20f and sedacryptine 20g. Optimised conditions have allowed the efficient production of 4a – c .…”

Methanesulfonic Acid Mediated Cyclization and Meyer–Schuster Rearrangement of γ‐Amino‐ynones: Access to Enantiopure Pyrrolidine Exocyclic Vinylogous Amides

“…The method presented herein provides a new rapid access to various enantiopure pyrrolidine vinylogous amides in good yields. Such compounds, which can be prepared by Eschenmoser coupling17 or Knoevenagel‐type reactions,18 have been used as intermediates in the synthesis of many natural compounds,19 such as anisomycin,20a apomitomycin,20b mesembrenone,20c desoxoprosophylline,20d cassine,19c pinidinone,20e deoxyfebrifugine,20f and sedacryptine 20g. Optimised conditions have allowed the efficient production of 4a – c .…”

Asymmetric Construction of Alkaloids by Employing a Key ω‐Transaminase Cascade

“…β‐Enaminones are vinylogous amides with unique reactivity and represent important intermediates in the synthesis of a variety of N ‐heterocyclic compounds . Specifically, six‐membered cyclic variants have been exploited for the preparation of a diverse array of bioactive piperidine alkaloids (Figure ), including pinidinone and related 2,6‐piperidine derivatives, apomitomycin, mesembrenone, desoxoprosophylline, cassine, deoxyfebrifugine, sedacryptine, selenopsine and the Coccinellidae defensive alkaloids, including hippodamine . However, despite their importance, there have been limited strategies reported for the enantioselective construction of chiral β‐enaminones.…”