Diastereo- and enantioselective synthesis of beta-amino cyclic ethers via the intramolecular reaction of gamma-alkoxyallylstannane with imine

The intramolecular Lewis acid mediated cyclization of gamma-alkoxyallylstan nanes 1, 2, and 14, bearing a hydrazone group at the terminus of the carbon chain, afforded exclusively the corresponding trans beta-amino cyclic ethe rs 3a, 4a, and 15, respectively. The Lewis acid mediated cyclization of gam ma-alkoxyallylstannane 5, having (R)-(+)-1-phenylethylamine as a chiral aux iliary, afforded exclusively traits beta-amino cyclic ether 6a with very hi gh diastereomeric excess (de) in very high chemical yields. The asymmetric cyclization of gamma-alkoxyallylstannane with imine 7 in the presence of ch iral titanium-BINOL complex 9, afforded predominantly cis beta-amino cyclic ether 8b with high enantiomeric excess tee). The chiral Lewis acid mediate d cyclization of racemic compound 38 containing phenyl as a substituent aff orded cis isomer 39 with very high enantiomeric excess (ee).