4-methylene-2-(1-pentyl)-tetrahydro-2H-pyran   、                                                                                      
4-methyl-2-(1-pentyl)-5,6-dihydro-2H-pyran                                                                                                                                                                                                                                                                                                          以4-methyl-2-pentyl-3,6-dihydro-2H-pyran (II-Bc) is obtained from 3-methyl-3-buten-1-ol and hexanal according to example 3 (Method B, specific conditions according to entry 6)的产率得到4-methyl-2-(1-pentyl)-3,6-dihydro-2H-pyran