TETRAHYDROPYRANYL ETHER DERIVATIVES

The tetrahydropyranyl group, commonly used in synthetic procedures to protect hydroxyl groups, appears not to be safe when peroxidising reagents are used with tetrahydropyranyl ether derivatives, because explosive peroxides, not destroyed by the usual reagents, are produced. 

TETRAHYDROPYRANYL ETHER DERIVATIVES and individually indexed compounds ... 

The conventional vinylidene complex could be isolated when the hydroxyl group was protected as the tetrahydropyranyl ether derivative reaction of this with acid immediately gave the cyclic carbene complex, even under mild conditions. The reaction is related to the formation of similar nickel(II)- and platinum(IV)-carbene complexes from the [Pg.71]

A 1,2-hydride shift has been invoked399 to account for the formation of p-methoxyphenylbutyraldehyde derivatives (337) during the treatment of />methoxy-benzyl-protected allylic alcohols (336) with zeolites. A similar C-glycosidation procedure involving Lewis acid-catalysed anomeric oxygen to carbon rearrangement of tetrahydropyranyl ether derivatives has been reported400 (see Scheme 82). It has been... 

Methyl-3-buten-l-yl tetrahydropyranyl ether See TETRAHYDROPYRANYL ETHER DERIVATIVES... 

Tetraazamacrocyclanemetal perchlorates, 391 Tetrahydropyranyl ether derivatives, 391 Tetra(N-methylpyridyl)porphine perchlorates, 391 Tetramethyl [14] tetraene-N8 metal perchlorates, 392... 

Treatment of alkynyl tri- -butyltin tetrahydropyranyl ether derivatives with BF3-OEt2 effects an anomeric oxygen to carbon rearrangement, furnishing the corresponding carbon-linked alkynol products (Equation (64)).218... 

The combination of triphenylphosphine with esters of trihaloacetic acids provides a reagent system for the stereo- and regio-selective conversion of alcohols into alkyl halides.The bromine-triphenylphosphine adduct has been used at low temperatures (-50 C in dichloromethane) for the removal of the tetrahydropyranyl protecting group from tetrahydropyranyl ethers derived from secondary and tertiary alcohols.The reactions of tertiary phosphines (and other trivalent phosphorus compounds) with iodine in aprotic solvents have received further study, a range of species being identified.The first reported study of the reactions of trivalent phosphorus compounds with monopositive astatine has led to the identification of stable complexes with triphenylphosphine, trioctylphosphine, and triethylphosphite. 

Hydroxycyclopropanecarbaldehyde (2) has not been isolated as the free acyloin, only the silylated or tetrahydropyranyl ether derivatives have been prepared. Attempts to effect the contraction of 2-hydroxycyclobutanone (1), by heating it in a sealed tube either alone (210°C) or with water (230°C) failed to bring about any reaction at all. The conclusion drawn was that while contraction almost certainly occurs, the equilibrium lies heavily on the side of the four-membered ring. ... 

A successful synthesis of muricholic acid was achieved by the sequence of reactions shown in Fig. 7 [Hsia et al. (44)]. The structure in ring B of VII was stabilized by the formation of the tetrahydropyranyl ether derivative (XXII). The ether linkage at position 6 would prevent the formation of the... 

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