Derrick L. J. Clive

Cyclofunctionalisation of unsaturated acids with benzeneselenenyl chloride : Kinetic and thermodynamic aspects of the rules for ring closure

Abstract Experimental procedures are described for the synthetically useful reaction by which olefinic acids are converted into lactones carrying a benzeneseleno-group. Data are presented to define some of the mechanistic details of this type of cyclofunctionalisation and kinetic and thermodynamic factors relevant to the Rules for Ring Closure are discussed. A nomenclature is introduced for a treatment of ring-fusion stereochemistry.

Synthetic studies related to compactin and mevinolin: A new synthesis of the lactone system.

Abstract (S)-Malic acid diethyl ester was converted into a precursor of the lactonic portion of compactin and mevinolin. The substance was coupled with benzyl p -tolyl sulfone and elaborated into the chiral lactone system of the natural products.

Radical annulation: a method for preparation of carbocycles

β-Acetylenic radicals, e.g., (6b) and (12), generated in three steps from epoxides or in two steps from α-halogenoketones, respectively, react with electron-deficient olefins to produce five-membered carbocycles by a process of conjugate addition and 5-exo-digonal closure.

Conversion of Olefins into Five-membered Nitrogen Heterocycles by Radical Cyclization

A partir de cyclohexene et de methylenecyclohexane et de N-phenylthiophtalimide, synthese de 2-(phenylseleno) cyclohexyl- et de 1-(phenylselenomethyl) cyclohexyl cyanamide; N-alkylation par des halogenures dalkyle ou de propargyle puis cyclisation en N-cyanoperhydroindoles ou N-cyano 1-azaspiro[4.5] decanes

2-(phenylseleno)prop-2-enenitrile: a three-carbon unit for radical cyclization

Successive reaction of enamines with 2-(phenylseleno)prop-2-enenitrile, lithium phenylacetylide, and triphenyltin hydride serves to generate carbocycles by a process of radical ring closure.

A synthetic equivalent for the butadienyl carbonium ion: use of 4-(trimethylsilyl)but-2-ynal for preparation of 1,3-dienes and macroexpansion of cyclic ketones

4-(Trimethylsily)but-2-ynal (3) is a synthetic equivalent for the butadienyl carbonium ion and can be used for preparation of terminal 1,3-dienes and for macroexpansion of cyclic ketones.

Synthesis of spiro-compounds related to fredericamycin A

Spiro-compounds [e.g., (8), (13)] that resemble the four central rings of the antitumour agent fredericamycin A have been synthesized by methods that are based on (i) intramolecular acylation and high-pressure Diels–Alder chemistry [(5)→(8)] or (ii) radical spiro-cyclization [e.g., (11)→(13)].

A new method for synthesis of five-membered carbocycles: use of the ester enolate rearrangement in conjunction with radical cyclization

4-(Phenylseleno)butyryl esters (2), easily prepared from allylic alcohols, are convertible into cyclopentanes by successive ester enolate rearrangement (2)→(3) and 5-exo-trigonal radical cyclization (4)→(6); this general process is efficient and the stereochemical result is predictable.

Synthesis of spiro-compounds: use of diselenoacetals for generation of quaternary centres by alkylation and radical cyclization

Ketones are readily converted viathe corresponding diphenyl diselenoacetals (2) into selenides (5) which undergo radical 5-exo cyclization to spiro-compounds (7) on treatment with triphenyltin hydride and azoisobutyronitrile; an analogous sequence serves for the preparation of spiro-lactones (12).

Synthetic applications of radical ring-opening: use of cyclopropylmethyl radicals

Cyclopropanation of cyclic allylic alcohols followed by radical deoxygenation leads, by peripheral ring-opening of the cyclopropylmethyl system, to alkyl-substituted cycloalkenes (Scheme 1); the alkyl group can itself be substituted (during the cyclopropanation stage), synthetic equivalents of allylic alcohols can be used, and the overall process occurs with predictable stereo- and regio-chemistry.