The total syntheses of (−)-herquline B (2) and a heretofore-unrecognized congener, (+)-herquline C (3), are described. The syntheses require 14 and 13 steps, respectively, and feature a key oxazoline reduction that sets the stage for piperazine construction.

The development of a concise total synthesis of (±)‐phyllantidine (1), a member of the securinega family of alkaloids containing an unusual oxazabicyclo[3.3.1]nonane core, is described. The synthesis employs a unique synthetic strategy featuring the ring expansion of a substituted cyclopentanone to a cyclic hydroxamic acid as a key step that allows facile installation of the embedded nitrogen‐oxygen (N−O) bond. The optimization of this sequence to effect the desired regiochemical outcome and its mechanistic underpinnings were assessed both computationally and experimentally. This synthetic approach also features an early‐stage diastereoselective aldol reaction to assemble the substituted cyclopentanone, a mild reduction of an amide intermediate without N−O bond cleavage, and the rapid assembly of the butenolide found in (1) via use of the Bestmann ylide.

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Longeracemine, a member of the Daphniphyllum family of alkaloids contains a novel carbon framework featuring a highly functionalized 2-azabicyclo[2.2.1]heptane core as part of an overall 5/6/5/5/6/5 skeleton. A synthetic intermediate...

The development of aconcise total synthesis of (AE)phyllantidine (1), am ember of the securinega family of alkaloids containing an unusual oxazabicyclo[3.3.1]nonane core,i sd escribed. The synthesis employs au nique synthetic strategy featuring the ring expansion of as ubstituted cyclopentanone to acyclic hydroxamic acid as akey step that allows facile installation of the embedded nitrogen-oxygen (NÀO) bond. The optimization of this sequence to effect the desired regiochemical outcome and its mechanistic underpinnings were assessed both computationally and experimentally.T his synthetic approach also features an early-stage diastereoselective aldol reaction to assemble the substituted cyclopentanone, amild reduction of an amide intermediate without NÀObond cleavage,and the rapid assembly of the butenolide found in (1) via use of the Bestmann ylide. AngewandteChemie Forschungsartikel Scheme 10. Deprotection of TBS ether in aldol adduct 18. Scheme 11. Ring expansion of acetonide-protected acyloxy nitroso 43. Scheme 12. Preparation of carbonate-protected acyloxy nitroso adduct 48.