Stereoselective total synthesis of (−)-conduramine F-1 via chiral 1,3-oxazine

Stereoselective Syntheses of (+)‐Broussonetine D and (+)‐Australine via a Functionalized Pyrrolidine from an Extended Chiral 1,3‐Oxazine

“…The preparation of functionalized pyrrolidine 6 is shown in Scheme and begins with anti , syn , syn ‐oxazine 4 , which was prepared using reported methods. [10a], [10b] Mesylate 10 , obtained from anti , syn , syn ‐oxazine 4 , was subjected to oxazine cleaving conditions using benzyl chloroformate in the presence of aqueous sodium hydrogen carbonate, which simultaneously induced cyclization, to yield functionalized pyrrolidine 6 .…”

“…We previously reported the syntheses of extended 1,3‐oxazines as chiral building blocks (Scheme ); we successfully applied them to the syntheses of conduramine F‐1,[10a] (+)‐hyacinthacine A 2 ,[10b] (–)‐sphingofungin B,[10b] (+)‐1‐deoxynojirimycin, 2,5‐dihydroxymethyl‐3,4‐dihydroxypyrrolidine [(+)‐DMDP], (+)‐2,5‐dideoxy‐2,5‐imino‐ d ‐glucitol [(+)‐DGDP],[10c] and (–)‐1‐deoxymannojirimycin [(–)‐DMJ]. [10c] As part of an ongoing research program aimed at the development of syntheses of biologically active compounds, we herein report the stereoselective syntheses of (+)‐broussonetine D ( 1 ) and (+)‐australine ( 2 ) via a functionalized pyrrolidine from an extended chiral 1,3‐oxazine.…”

Stereoselective syntheses of 3-aminocyclooctanetriols and halocyclooctanetriols

“…The cyclic sulphate moiety in 9 was reacted with sodium azide in DMF at 80 °C followed by acidic hydrolysis of the resulting acyclic sulphate ester to give azidotriol 10 as a single stereoisomer in 97% yield (Scheme 2). For further structural proof, the For the synthesis of the other aminocyclooctanetriol (18), the diol 6a [34] was reacted with m-CPBA to give trans-epoxide isomer 13 [34] (79% yield) as the sole product (Scheme 3). Ring opening of trans-epoxide 13 by HBr(g)-MeOH gave bromotriol 14, which is an ideal substrate for the synthesis of the aminocyclooctanetriol (18).…”

“…One of the most important conduramines (4) is valienamine (3) [17], is found as a building block in several aminoglycoside antibiotics [2]. Furthermore, conduramines (4) and their derivatives are used as both inhibitors of glycosidases and also useful intermediates in organic synthesis [18]. One of the derivatives of cyclitols is also halocyclitols, in which one of the hydroxyl groups is replaced by a halogen.…”

“…Many methods have been previously reported for the synthesis of aminocyclitols containing five-and six-membered rings, along with their diverse biological activities [1][2][3][16][17][18][19][20][21][22][23][24][25][26][27]. However, only a limited number of synthetic methods are available for the synthesis of seven- [28,29], eight- [30][31][32][33][34][35][36][37][38][39], and nine- [36] membered aminocyclitols.…”