苯甲醛   、                                                                                      
2-Dimethylamino-3,3-dimethyl-cyclobutanecarboxylic acid ethyl ester                                                                                                                                                              在
                                                                                                                                                                                 
盐酸   、                                                                                                  
四氯化钛                                                                                                                                  作用下,
                                                                                                                                                                                                                            生成                                                 (2S,3S)-6-Hydroxy-5,5-dimethyl-2-phenyl-tetrahydro-pyran-3-carboxylic acid ethyl ester   、                                                                                             (2S,3R)-6-Hydroxy-5,5-dimethyl-2-phenyl-tetrahydro-pyran-3-carboxylic acid ethyl ester