Dioxaphosphorinane chair to half-chair conversion caused by cis- to trans-enol transformation of the β-ketoester substituent

Polozov, A. M.; Литвинов, И. А.; Kataeva, О. N.; Stolov, Andrei A.; Yarkova, E. G.; Khotinen, A. V.; Klimovitskii, E. N.

doi:10.1016/0022-2860(95)08941-n

Cited by 3 publications

(4 citation statements)

References 19 publications

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“…The bromo substituent is in the opposite axial position to the phenoxy substituent and the methylbromo group is in an opposite equatorial position to the P═O bond. The bond lengths and angles in (I) are within normal ranges (Allen et al, 1987) and are comparable to related structures (Jones et al, 1984;Polozov et al, 1995). The closest Br•••Br distance is 3.5484 (9) Å.…”

Section: Methodssupporting

confidence: 63%

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5-Bromo-5-bromomethyl-2-phenoxy-1,3,2-dioxaphosphorinan-2-one

et al. 2008

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In the title 1,3,2-dioxaphosphorinane derivative, C10H11Br2O4P, the 1,3,2-dioxaphosphorinane ring adopts a chair conformation, having the P=O bond equatorially oriented and the phenoxy group axially oriented. The bromo substituent is in an axial position opposite to the phenoxy group and the bromomethyl group is in an equatorial position opposite to the P=O bond. In the crystal packing, molecules are linked through weak C—H⋯O and C—H⋯Br interactions to form chains along the b axis. The chains are arranged into sheets parallel to the ab plane. In adjacent sheets, molecules are arranged in an antiparallel fashion. Intermolecular C—H⋯π interactions are also observed.

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Section: Methodssupporting

confidence: 63%

“…For ring conformations, see: Cremer & Pople (1975). For related structures, see, for example: Jones et al (1984); Polozov et al (1995). For related literature and applications of dioxaphosphorinane derivatives, see, for example: Goswami (1993); Goswami & Adak (2002); Pilato et al (1991); Taylor & Goswami (1992).…”

Section: Related Literaturementioning

confidence: 99%

5-Bromo-5-bromomethyl-2-phenoxy-1,3,2-dioxaphosphorinan-2-one

et al. 2008

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“…However, conformation B 2 can become predominant for the epimeric pairs of D-ring-fused 1,3,2-dioxaphosphorinanes and also for their 1,3,2-oxazaphosphorinane analogues, where the five-membered ring D is part of a more rigid estrane framework. In this regard, we recently reported the syntheses and stereochemical analyses of dioxa- (27 29) and oxazaphosphorino [16,17] The related epimers a and b of 27 29 and 46 50 were separated by column chromatography and their P configurations were assigned by means of 31 configuration and the substituent preferences (Scheme 6). The P substituent is situated pseudo-axially in the a series (Y cis to H 17 ), and pseudo-equatorially in the b series (Y trans to H 17 ) of compounds.…”

Section: Synthesis and Conformational Study Of Ring-condensed 132-dmentioning

confidence: 99%

“…The interconversion between the two alternative chair forms, however, is normally rapid in solution [4][5][6][7], unless there is a conformational bias towards the population of one or other conformer by very bulky groups on the P-ring and in rigid polycycles. In these latter cases, one of the chair conformers or an unusual intermediate twist [15], half-chair [16] or boat [17] form becomes predominant and these systems can be regarded as anancomeric [7]. The 1,3,2-oxazaphosphorinanes may have an enhanced propensity towards twist conformations as compared with the 1,3,2-dioxa series, although the ring N substituent can have a significant modulating effect [18].…”

Section: Introductionmentioning

confidence: 99%

6-Membered P-Heterocycles: Ring-Condensed 1,3,2-Diheterophosphorinane 2-Chalcogenides

Frank¹,

Wölfling²

2007

COC

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Literature publications (up to the end of 2006) relating to the synthesis, biological significance and conformational behaviour of carbocycle-and heterocycle-condensed six-membered tetracoordinate P(V) 1,3,2-diheterophosphorinanes are reviewed. The replacement of carbon atoms of cyclohexane by P and O and/or N to form 1,3,2-dioxa-, 1,3,2-oxaza-or 1,3,2-diazaphosphorinanes introduces lone pair electrons instead of hydrogens and changes the bond angles and bond lengths, and can thereby lead to significantly different stereostructural preferences of the hetero ring as compared with those of cyclohexane. Although monocyclic 1,3,2-diheterophosphorinanes often exist in a chair conformation in both the solid and solution states, the existence of conformations other than a chair can predominate in some cases for steric and stereoelectronic reasons associated with the presence of bulky groups on the P-containing ring or in polycyclic rigid systems.After a brief account on the most important pharmacological and stereochemical features, involving the configuration assignment and conformation determination of P-diheterophosphorinanes, the present review mainly focuses on the synthesis and stereostructural studies of carbo-and heterocycle-condensed derivatives, where the fused ring may exert considerable effects on the conformational behaviour of the P-hetero ring.

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