[reaction: see text] The asymmetric propargylboration of aldehydes at -78 degrees C in <3 h with 1 provides silylated alpha-allenyl carbinols 6 (60-87%) in high ee (94% to >98% ee). The reagents 1 are easily prepared in both enantiomeric forms with a simple Grignard procedure and air-stable borinate complexes 2. The ozonolysis of 6 proceeds smoothly through an acylsilane intermediate to give a TMS
[反应:参见正文]醛在-78摄氏度下于<3 h内与1进行的不对称炔丙基硼化可在高ee(94%至> 98%ee)中提供甲
硅烷基化的α-烯基
甲醇6(60-87%)。试剂1可以通过简单的
格氏试剂和对空气稳定的
硼酸酯络合物2轻松制备成对映体形式。6的
臭氧分解反应通过酰基
硅烷中间体平稳进行,得到TMS酯,该酯被
水解成α-羟基酸。
水。