The enantioselective synthesis of 2,3,5-trisubstituted tetrahydrofurans 3 has been achieved using a chiral titanium-BINOL complex as catalyst for the vinylogous Mukaiyama aldol reaction of bis(silyl) diendiolate 1 and an aldehyde. The ensuing BF·OEt-mediated Prins-type cyclization with a second aldehyde gave rise to 2,3,5-substituted tetrahydrofurans 3 with generally good yields and excellent stereocontrol. In this process, three new σ-bonds and three new stereogenic centers were generated in a one-pot process.
View Article and Find Full Text PDFThe development of a direct and highly stereoselective synthesis of 2,3,5-substituted tetrahydrofurans has been accomplished through a combination of batch- and microchip-MS-experiments. This sequential transformation comprises a Lewis acid-mediated reaction of bis(silyl) dienediolate 1 and a broad range of aldehydes, furnishing products with three new σ-bonds and three stereogenic centers in a one-pot process with typically good yields and excellent stereoselectivity. Key steps which have been elucidated primarily with microchip-MS-experiments include a vinylogous aldol reaction and a Prins-type cyclization.
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