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The trimethylsiyl ether 7 derived in two steps from camphor underwent ring expansion via an acylion rearrangement to afford two products (8 and 9) when desilylation was attempted. Compound 9 was stable but 8 was oxidized in air to homocamphoric acid anhydride 11. Key words: camphor, acyloin rearrangement.

Alkylations of anions derived from dipeptides with a glycine at the C-terminus have been investigated. A hydrocarbon sedition in the N-terminal residue does impart some asymmetric induction. The use of a chiral ester derivative provides the potential for double asymmetric induction and good selectivity. With an aspartyl residue at the N-terminus, problems were encountered due to competing side reactions. The use of an azetidinone could circumvent some of these, but the observed induction was not high.

The crystal structures of 1-azoniatricyclo[4.4.4.01,6]tetradecane bromide (1) and 1-azoniatricyclo[4.4.3.01,6]tridecane bromide (2) are reported. Compound 1, C13H24NBr, crystallizes in space group ...

Distillation of ω-carboxyalkyl lactams from soda-lime leads to the formation of bicyclic enamines or imines with concomitant loss of carbon dioxide and water. Monoamides of dicarboxylic acids afford cyclic ketones. A mechanistic rationale is presented and it is concluded that the reaction is a variant of the classical Ruzicka cyclization of dicarboxylic acids. The method allows the regiospecific formation of iminium salts of bicyclic nitrogen heterocycles.

The reaction of β-mercaptoaldehydes and ketones with vinylphosphonium salts results in the ready formation of 3,6-dihydro-(2H)thiopyrans. The presence of an α-substituent on the salt blocks this re...

The reaction of α-mercaptoaldehydes and ketones with 1,3-butadien-1-yltriphenylphosphonium salts (4) unexpectedly leads to 3-vinylthiophenes and triphenylphosphine. This result is attributed to the...

2,5-Dihydrothiophenes are dehydrogenated to thiophenes in high yield using chloranil in tert-butanol or pyridine. The presence of a fully substituted carbon atom blocks the reaction. The method all...

The rationale for considering 1-azoniapropellane salts as potential chiral phase-transfer catalysts is presented. The synthesis of two examples of these types of molecules is outlined and their eff...

The complete carbon-13 nmr spectra of 16 alkylated 2,5-dihydrothiophenes and 10 sulfones derived from them are reported. No significant interactions between C-2 substituents and C-5 are noted and stereochemical determinations based on this γ effect are not possible. On oxidation to the sulfones, C-2 and C-5 are dramatically deshielded but C-3 and C-4 are shielded. A possible explanation for this effect is presented.

Regiospecific formation of 10-allyl-1-ketoquinolizidine (7) is achieved in high yield by a [2.3] sigmatropic rearrangement of N-allyl-1-ketoquinolizidinium bromide (6). Wolff–Kischner reduction of ...

Reaction of tributyltin hydride with a variety of organic sulfides gives results which depend on the structure of the starting material. Acyclic sulfides undergo desulfurization leading to hydrocarbons in varying yields. However, 2,5-dihydrothiophenes give dienes and 3,6-dihydro-2H-thiopyrans are inert.

The preparation of a series of vinyltriphenylphosphonium salts, all of which bear a substituent on the carbon attached to phosphorus, is described. Yields are generally poor unless a symmetrical secondary allylic halide can be used. The use of these salts in the preparation of substituted 2,5-dihydrothiophenes has been examined. In general, reaction times are increased and product yields decreased relative to the reactions of the unsubstituted salts previously reported. This result is ascribed to steric inhibition of the intramolecular Wittig reaction.