Paterno-Biichi reaction furan

One of the best-known and highly useful photochemical synthetic procedures is the Paterno-Biichi reaction [17]. This transformation has also been adapted as basic principle for domino processes by different research groups. Agosta and coworkers published a procedure by which tetrasubstituted furans such as 5-65 can be built up from 5-61 and 5-62 (Scheme 5.13) [18],... 

III. The Paterno-Biichi Reaction on Pentaatomic Heterocycles Different from Furan... 

The diastereoselective Paterno-Biichi reaction of benzoin 128 with benzo[ ]furan 82 was utilized to stereoselec-tively construct a [6-5-4] tricyclic heterocycle 129 (Equation 110). The observed diastereoselective excess was also explained <2004TL3877>. 

The photoinduced Paterno-Biichi reaction of 1-acetylisatin 130 with benzo [3]furan 82 was employed to make a structurally interesting spiro-type molecule 131 in good yield, as depicted in Equation (111) <2002J(P1)345>. 

The second report concerns the factors controlling the stereoselectivity of Paterno-Biichi reactions between aromatic aldehydes and 2,3-dihydrofuran32-34, Whereas furan yields exclusively 6-phenyl-2,7-dioxabicyclo[3.2.0]hept-3-ene (9) with the aryl substituent in the ecto-posi-tion 10,32-36, 2,3-dihydrofuran forms the eWo-compound 11, interestingly this occurs even with sterically demanding substituents. 

High selectivity has been obtained in the Paterno-Biichi reaction of aldehydes with furans and this reaction has formed the basis of a number of total syntheses. Thus, photocycloaddition of furan with nonanal gave the exo product 170, which was converted to the antifungal metabolite avenaciolide (3.115). 

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