SCOPUS 정보 검색 플랫폼

Volumn 43, Issue 34, 2002, Pages 6011-6014

Towards a total synthesis of (-)-cephalotaxine: Construction of the BCDE-tetracyclic core

Author keywords

[No Author keywords available]

Indexed keywords

BENZAZEPINE DERIVATIVE; CARBENOID; CEPHALOTAXINE; ESTER DERIVATIVE; N TERT BUTYLOXYCARBONYLPROLINE METHYL ESTER; UNCLASSIFIED DRUG;

ARTICLE; CYCLIZATION; DRUG SYNTHESIS; STEREOCHEMISTRY;

INSERTION SEQUENCES;

EID: 0037136167 PISSN: 00404039 EISSN: None Source Type: Journal
DOI: 10.1016/S0040-4039(02)01219-4 Document Type: Article

Times cited : (43)

References (27)

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- Paudler, W.W.¹ McKay, J.²

12
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- Tietze, L.F.¹ Schirok, H.²

18
- 0035847228
- (2001) J. Org. Chem. , vol.66 , pp. 143
- Taber, D.F.¹ Neubert, T.D.²

20
- 0009953369
- 3) but we have been unable to find a suitable assay to determine the % enantiomeric excess. Previous studies from our research group, however, have shown that alkylidene carbene 1,5-CH insertions of this type proceed with retention of stereochemistry (see Ref. 6).

22
- 0009954265
- Tietze et al. showed that a similar precursor to 4 could be cyclised with Herrmann's catalyst to produce a tetracyclic product in 81% yield (see Ref. 5a). We believe that steric interaction between the palladium catalyst and the methyl substituent on the olefin in 4 facilitates preferential coordination to the tertiary amine rather than the trisubstituted olefin.

23
- 33748621833
- and references cited therein
- (1995) Angew. Chem., Int. Ed. Engl. , vol.34 , pp. 1348
- Guram, A.S.¹ Rennels, R.A.² Buchwald, S.L.³

24
- 0034838172
- (2001) J. Am. Chem. Soc. , vol.123 , pp. 6989
- Littke, A.F.¹ Fu, G.C.²

26
- 0009905222
- Compound 15 contains a particularly acidic methylene moiety, and we believe that initial deprotonation at this site by KHMDS results in the subsequent 1,1-elimination reaction being retarded.

27
- 0009938841
- We believe that the modest overall yield observed for the formation of 18 from 16 is due to decomposition of the intermediate spirocyclic secondary amine 17 under the acidic deprotection conditions. Control experiments show that samples of the ammonium salt of 17 decompose over time, even at -20°C. We are currently examining the use of different protecting groups for the secondary amine that can be removed under neutral or basic conditions.

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