Changing the Reaction Pathway of Silyl-Prins Cyclization by Switching the Lewis Acid: Application to the Synthesis of an Antinociceptive Compound

Terminal Cyclopropylsilyl Alcohols as Useful Key Units to Access 2,3,4,6-Tetrasubstituted Tetrahydropyran Scaffolds by Stereocontrolled Prins Cyclization

In this study, the use of terminal cyclopropylsilyl alcohols in Prins cyclization is reported as a very efficient methodology for the preparation of polysubstituted tetrahydropyrans, in which three new stereogenic centers have been created in a single pot. The reaction is general for a wide variety of aldehydes (alkylic, vinylic, aromatic, or dialdehydes), different types of alcohols, and halogenation agents providing high yields and excellent diastereoselectivity 2,3,4,6-tetrasubstituted tetrahydropyranyl frameworks. Interestingly, diastereomeric alcohols provide the same tetrahydropyranyl derivatives, showing that the reaction mechanism proceeds through common intermediates.

Towards an efficient methodology for the synthesis of functionalized dihydropyrans by silyl-Prins cyclization: access to truncated natural products

We herein present a selective methodology for the synthesis of disubstituted dihydropyrans by silyl-Prins cyclization of Z-vinylsilyl alcohols mediated by trimethylsilyl trifluoromethanesulfonate (TMSOTf). The reaction features broad substrate scope, short reaction times and ease of process scale-up. Moreover, to showcase the applicability of the proposed method, we also report a facile and linear synthesis of analogues of rhopaloic acid and natural doremox fragrance.