- Chemoenzymatic Formal Total Synthesis of Pancratistatin from Narciclasine-Type Compounds via Myers Transposition: Model Study for a Short Conversion of Narciclasine to Pancratistatin
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A formal total synthesis of pancratistatin was accomplished by conversion of advanced intermediates, used in the synthesis of narciclasine, to pancratistatin precursors via Myers' reductive transposition as the key strategic step. The synthesis began with the whole cell fermentation of m -dibromobenzene with JM109(pDTG601a), a recombinant strain that over-expresses toluene dioxygenase, which provided the corresponding cis -dihydrodiol 16 as a single isomer with complete optical purity. The key reductive transposition of the allylic alcohol 8a to olefin 9a allowed for further installation of the C-1/C-2 trans -diol, required for the pancratistatin scaffold, through the introduction of a cyclic sulfate and its subsequent opening. The formal synthesis of pancratistatin was accomplished in 14 steps (12 operations) from commercially available m -dibromobenzene. Experimental and spectral data are provided for all new compounds.
- Lapinskaite, Ringaile,Ghavre, Mukund,Rintelmann, Chelsea L.,Bedard, Korey,Dela Paz, Helen E.,Hudlicky, Tomas
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supporting information
p. 2896 - 2900
(2017/10/06)
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- A stereospecific palladium-catalyzed route to monoalkyl diazenes for mild allylic reduction
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(Chemical Equation Presented) One step beyond: The first single-step stereospecific transition-metal-catalyzed conversion of allylic electrophiles into monoalkyl diazenes is described. This synthesis of allylic monoalkyl diazenes offers a new strategy for asymmetric synthesis by the reduction of optically active substrates or the use of chiral catalyst systems. Sensitive substrates are reduced in a highly selective manner. Ar = 2-NO2C 6H2.
- Movassaghi, Mohammad,Ahmad, Omar K.
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supporting information; experimental part
p. 8909 - 8912
(2009/05/26)
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- N-isopropylidene-N′-2-nitrobenzenesulfonyl hydrazine, a reagent for reduction of alcohols via the corresponding monoalkyl diazenes
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The reagent N-isopropylidene-N′-2-nitrobenzenesulfonyl hydrazine (IPNBSH) is used in the reduction of alcohols via the loss of dinitrogen from transiently formed monoalkyl diazene intermediates accessed by sequential Mitsunobu displacement, hydrolysis, and fragmentation under mild reaction conditions.
- Movassaghi, Mohammad,Ahmad, Omar K.
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p. 1838 - 1841
(2007/10/03)
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- Enantioselective total synthesis of (-)-acylfulvene and (-)-irofulven
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(Chemical Equation Presented) Antitumor agents (-)-acylfulvene and (-)-irofulven are prepared in an approach that employs the powerful enyne ring-closing metathesis reaction to secure the spiro-bicyclic AB rings. Other key features of this synthesis include an efficient aldol-based introduction of the stereocenter at C2, a diazene-mediated reductive allylic transposition, and a ring-closing metathesis/oxidation sequence.
- Movassaghi, Mohammad,Piizzi, Grazia,Siegel, Dustin S.,Piersanti, Giovanni
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p. 5859 - 5863
(2007/10/03)
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- Promotion of Dehydrazination by Nitrobenzensulfonyl Group from Phosphorus-hydrazone Adducts
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Dehydrazination of adducts of phenylsulfonylhydrazones and phosphorus compounds was promoted by a nitro substituent on the ring to afford derivatives of a phosphine oxide and phosphonates.
- Yamashita, Mitsuji,Takeuchi, Jun,Nakatani, Kaname,Oshikawa, Tatsuo,Inokawa, Saburo
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p. 377 - 378
(2007/10/02)
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