Patemo-Buchi reaction oxetane synthesis

The Patemo-Buchi reaction has been studied mechanistically ever since Patemo and Chieffi first reported that the photoreaction of ketones and alkenes produced, unexpectedly, the corresponding oxetane. Indeed, a recent surge of studies of the photoreaction mechanism has stimulated numerous applications in organic synthesis. 

In addition to the functionalization protocols of Schemes 13 and 14, vinylic substitution reactions involving metalation and palladium-mediated carbon-carbon bond formation have been formulated," which further broaden the variety of stmctural types available from the Patemo-BUchi reaction. For example, deprotection and stannylation of photoaldol (133), followed by refimctionalization of the a-enol ether position of vinylstannane (134), gave the substituted oxetane (135) in good overall yield. Similar functionalization of bicyclic oxetane (136) via exo-face dihydroxylation and acid-catalyzed reorganization of the acetal to the protected 3-deoxy-( )-streptose (137) has been reported, which illustrates the synthetic utility of such processes in the synthesis of polyoxygenated materials." ... 

Irradiation of the enone (80) at 282 nm brings about the formation of the oxetane (81), and this process has been used as a key step in the development of a synthesis of 2,7,9-trimethylenetricyclo[4.3.0.0 ]non-4-ene. Such intramolecular additions are popular methods for the formation of polycyclic compounds that can be used as starting materials in syntheses. An efficient example of this from earlier years is the formation of the oxetane (82,90%) from the intramolecular cyclization of the enone (83). The oxetane formed is a key intermediate in a new efficient route to enrfo-hirsutene. ° A review of the application of the Diels-Alder/Patemo-Buchi reaction as an approach to di- and tri-quinanes has been published. ... 

The synthesis of oxetanes from alkenic precursors has been demonstrated and the range and scope of Patemo-BUchi photocycloadditions are broad. In general, both the reaction regioselectivity and stereoselectivity can often be predicted by considering the reaction mechanism (Section 2.4.2) for example, the directing effects of alkene substituents are readily understood. Synthetic applications are numerous owing to the rapid stereocontrolled assembly of multifunctional targets. 

Reviews of the Patemo-Buchi photocycloaddition reaction for the synthesis of mono- and bi-cyclic oxetanes <00SL1699> and the stereoselective synthesis of oxetanones are available... 

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