1978
DOI: 10.1021/jo00418a025
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Bicyclo[2.2.1]heptane-2,5-dione: its preparation and reaction with nucleophiles

Abstract: Notessupport and Professor F. E. Ziegler for many helpful discussions. J.G.G. is grateful to the National Science Foundation for a Predoctoral Fellowship.

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Cited by 27 publications
(13 citation statements)
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“…However, instead of relying on the known enantioselective, but multistep approach to 6/ent-6 from norbornadiene (7), [8] we employed the readily available racemic form of the diketone (rac-6), [9] and resolved the racemic mixture of DIANANE at a later stage. As summarized in Scheme 2, the N,N'-bistosylates of DIANANE (8 and ent-8) were efficiently separated by preparative HPLC on a chiral stationary phase.…”
Section: Dedicated To Professor Emanuel Vogel On the Occasion Of His mentioning
confidence: 99%
See 1 more Smart Citation
“…However, instead of relying on the known enantioselective, but multistep approach to 6/ent-6 from norbornadiene (7), [8] we employed the readily available racemic form of the diketone (rac-6), [9] and resolved the racemic mixture of DIANANE at a later stage. As summarized in Scheme 2, the N,N'-bistosylates of DIANANE (8 and ent-8) were efficiently separated by preparative HPLC on a chiral stationary phase.…”
Section: Dedicated To Professor Emanuel Vogel On the Occasion Of His mentioning
confidence: 99%
“…Typical reaction conditions [2,5] comprised 10 mol % of CrCl 3 , an excess of Mn and Me 3 SiCl, and in situ preparation of the Cr II complex, in the presence of NEt 3 and MeCN as solvent ( Table 1). Enantiodivergent synthesis of (S,S)-5 and (R,R)-5. a) HCO 2 H, reflux, 84 %; [9] b) Jones reagent, 44 %; [9] c) NH 2 OH·HCl, EtOH, reflux, 1 h; d) NiCl 2 , NaBH 4 , MeOH, À35 8C to À20 8C, 1 h, 70-75 % (over two steps); e) TsCl, NEt 3 , CH 2 Cl 2 , À78 8C to RT; f) crystallization from MeOH, 35 % (over two steps); g) preparative HPLC, Chiralpak AD, 50 cm, 5 cm diameter, flow: 80 mL min À1 , eluent: hexane/isopropanol 60:40, retention times: 24-33 min for (R,R)-8 and 46.5-62.5 min for (S,S)-8; h) Li, NH 3 , À33 8C, 80 min, 85 %; i) 3,5-di-tertbutyl salicylic aldehyde, MeOH, RT, 30 min, 76-81 %. After optimization of the reaction parameters (solvent, concentration, and temperature), the corresponding homoallylic alcohol was obtained with high enantioselelectivity (90 % ee) and good yield (72 %; Table 1, entry 1).…”
Section: Dedicated To Professor Emanuel Vogel On the Occasion Of His mentioning
confidence: 99%
“…Consequently, the pure enantiomers of DIANANE 9 (that is, ( S,S )‐ 9 and ( R,R )‐ 9 ) can be prepared from the enantiomerically pure diketone 6 and ent ‐ 6 , respectively. However, instead of relying on the known enantioselective, but multistep approach to 6 / ent ‐ 6 from norbornadiene ( 7 ),8 we employed the readily available racemic form of the diketone ( rac ‐ 6 ),9 and resolved the racemic mixture of DIANANE at a later stage. As summarized in Scheme , the N,N ′‐bistosylates of DIANANE ( 8 and ent ‐ 8 ) were efficiently separated by preparative HPLC on a chiral stationary phase.…”
Section: Methodsmentioning
confidence: 99%
“…reported an efficient and enantioselective route to hydroxyfuran acetal fragment 77 (Scheme ) 49. The starting point in this approach was chiral alcohol 72 , prepared by kinetic resolution of diketone 71 50 with baker's yeast 5153. The carbonyl group of 72 was then protected as its O ‐xylidenedioxy acetal and the resulting compound subjected to Swern oxidation conditions.…”
Section: Synthesis Of Azadirachtin Hydroxyfuran Acetal Fragmentsmentioning
confidence: 99%