Total synthesis of (+)-Valyldetoxinine and (−)-detoxin D1

A Shimizu Non‐Aldol Approach to the Formal Total Synthesis of Palmerolide A

“…The synthesis of acid fragment 90 embarked with the protection of allylic alcohol 57 as its TIPS ether and subsequent cleavage of TBS ether generated the alcohol 88 35. After the oxidation of alcohol 88 , the resultant aldehyde was subjected to the Wittig reaction to produce the conjugated ester 89 .…”

A straightforward synthesis of (2S,3R)-3-hydroxyproline and trans-(2R,3S)-2-hydroxymethyl-3-hydroxypyrrolidine

“…The mixture was estracted with EtOAc (3 x 100 ml), the combined organic extracts were washed with brine (100 ml) and dried with Na2SO4. Evaporation of the solvent under reduced pressure gave a residue which was purified by flash chromatography (CHCI3/MeOH, 9:1) to give 4 (7): To a solution of chloride 5…”

Muscarine, oxazole, imidazole, thiazole, and peptide alkaloids, and other miscellaneous alkaloids

“…Biogenetically these contiguous rings are derived by cyclization and oxidation of di-or triserine peptide intermediates and a synthesis has been published utilizing this pr~cedure.~' A new procedure has been reportedla that uses a repetitive rhodium-acetate-catalysed cycloaddition Reagents: i, Dimethyl diazomalonate (1.5 eq), [Rh,(OAc),] (2 mol YO), CHCl,, reflux; ii, LiAlH, (0.8 eq), THF, -78 "C, 3 hrs to rt; iii, Oxalyl chloride, DMSO, TEA, CH,Cl, ; iv, NH,OH * HCl, K,CO,, EtOH ; V, (CF,CO,)O, TFA, CH,Cl,, -78" to 0 "C Scheme 6 reaction of diazomalonates with nitriles. The protected cyanohydrin (39) underwent cycloaddition with dimethyl diazomalonate under the influence of rhodium acetate to give the oxazole ester (40). Conversion into the nitrile (41) in four steps allowed a second cycloaddition sequence to be utilized giving the dioxazole (42).…”