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Attempted imine formation between 3-hydroxycamphor and tert. butyl glycinate led to 8 the substitution product at the 3-position. Zinc-acetic acid treatment of 8 afforded 3-acetoxycamphor. Alkylation of the imine from from norcamphor and tert. butyl glycinate gave no stereoselection. Alkylation of the imine from from 10-hytdroxymethylcamphor and tert. butyl glycinate gave stereoselectivities inferior to those obtained from the imine of camphor itself ( 1 ) but aldol condensation with benzaldehyde, a reaction not possible with 1, was affected in 71% yield.

In the presence of an allylic bromide, aldehydes, but not ketones, react with cyanide ion under phase-transfer catalysis to give cyanohydrin allyl ethers which can be converted to ketones. Other alkylating agents and nucleophiles give different results. Replacing the allylic bromide with acetic anhydride leads to cyanohydrin acetates.

Formolysis of 1,5-cyclooctadiene monoepoxide (1) has been shown to give only ca. 25% of products of transannular reactions. The difference between this result and those from the solvolyses of cyclooctene oxide and 4-cyclooctenyl brosylate is attributed to conformational and ring-strain effects.

Dipole moments are reported for trimethylene sulfite and 11 alkyl derivatives in a variety of solvents (C6H12, CCl4, C6H6, dioxan). The variation of dipole moment with solvent for one of the 5-t-butyltrimethylene sulfite isomers is confirmed, but this behavior is not shown by the other compounds. This latter fact is used to rule out rapid chair–chair interconversion for these compounds. Recent ultrasonic absorption experiments are reinterpreted in the context of vicinal electron pair interactions and their effect on conformational analysis of sulfites and similar six-membered compounds. The result is a general scheme which is consistent with available information and which we believe is preferable to analysis of these compounds by analogy with cyclohexane.

Reinvestigation of the acetolysis of 5,5-diphenylcyclononyl tosylate (1) has confirmed the absence of any transannular processes and deamination of the corresponding amine 16 gave a similar resuit. Trifluoroacetolysis of 1 caused extensive transannular hydride migration but no phenyl migration. The former may be due to secondary acid-catalyzed rearrangements.

Using the reaction between four representative vinylphosphonium salts and three α-mercaptoaldehydes, 12 3,4-unsubstituted 2,5-dihydrothiophenes(1) were prepared. The reaction proceeds in excellent yields under mild conditions. The use of these compounds in the synthesis of dienes is indicated.

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.

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 allows a flexible regiospecific synthesis of thiophenes in high yield from readily available starting materials.

The addition of iodine azide to 2-cyclopentenone led to the formation of 2-iodo-2-cyclopentenone. A similar reaction with 2-cyclohexenone afforded the expected addition products in addition to 2-iodo-2-cyclohexenone.

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.

Condensation du succinaldehyde et de benzylamine en presence de KCN: obtention de benzyl-1 pyrrolidinedicarbonitrile-2,5; etude des diastereoisomeres obtenus; application a d'autres amines (phenylglycinol, norephedrine)

L'epoxydation conduit au melange 1:1 des cis- et trans-epoxy-3,4 cyclohexanemethanols et non au stereoisomere trans de facon predominante