Subject Prins reaction

Besides the patent literature very few scientific reports are devoted to this subject /7,8/, and therefore a systematic investigatioi is needed. Our paper is intended to study the behaviour of some zeolites in Prins reaction and to emphasize the correlation between the zeolite acidity and its catalytic performances. 

Diels-Alder reaction to give 226 as an intennediate. When 226 was subjected to healing, an aza-Prins reaction followed by loss of a proton afforded 228 in 77 % overall yield for the entire sequence commencing with diol 224. This late-stage intermediate was readily utilized to complete the total synthesis of the squalene-derived natural product methyl homosecodaphniphyllate (229) [114]. This masterful synthesis qualifies, without doubt, as one of the all-time triumphs in natural products synthesis [116],... 

In the laboratory of R.D. Rychnovsky, the segment-coupling Prins cyciization was utilized for the total synthesis of (-)-centrolobine. This approach avoided the common side reactions, such as side-chain exchange and partial racemization by reversible 2-oxonia Cope rearrangement, associated with other Prins cyciization reactions. The substrate -acetoxy ether was subjected to SnBr4 in DCM, which brought about the formation of the all-equatorial tetrahydropyran in good yield. 

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