Syntheses of Alkylidene cyclobutanes

The synthesis of alkylidene cyclobutanes from l-(-seleno) cyclobutyl carbinols is much more facile than of those bearing a cyclopropyl moiety. It resembles the transformation of other (P-hydroxyalkyl) selenides to olefins 7 9,11,12). 

Synthesis of Alkylidene Cyclobutanes from l-( 1-Seleno) Cyclobutyl Carbinols andfrom l-(l-Hydroxy)-l-(V-selenoalkyl) Cyclobutanes 

Synthesis of Alkylidene Cyclobutanes from l(l-Silyl) Cyclobutyl Carbinols 

The reactions reported for the synthesis of alkylidene cyclopropanes from l-(l-Silyl) 

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Syntheses of Alkylidene cyclobutanes from 1-Alkyl-l-selenocyclobutanes... 

Syntheses of Alkylidene cyclobutanes Via the Selenoxide Route The selenoxide route which was particularly inefficient with cyclopropyl derivatives in this case proved suitable. The reaction is completely regioselective in the case of P-hydroxy selenides, which produce exclusively the allyl alcohols possessing the endo-cyclic double bond (Scheme 39)s7), whereas a mixture of endo and exo olefins is... 

Syntheses of Alkylidene cyclobutanes Via the Selenonium Route Much greater regioselectivity in favor of the endocyclic isomer is observed when the selenonium route is used (Schemes 40 b, 41 b). This is probably due, although no... 

Syntheses of Alkylidene cyclopropanes and Alkylidene cyclobutanes by Formal Elimination of a Selenenyl Moiety and a Hydrogen... 

Syntheses of Alkylidene Cyclopropanes and Cyclobutanes by formal Elimination of a Hydroxyl Group and a Heteroatomic Moiety The methods discussed above, although efficient, possess important limitations. They do not permit, for example, the synthesis of tetrasubstituted alkylidene cyclopropanes due to the unavailability of the starting selenides, the alkylation of a-selenocyclopropyllithiums with sec-alkylhalides being not feasible at present. 

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