prepared in 83% yield from stannyloxazolidine 4. Grignard additions to the formyl group of compound 7 in the presence of Lewis acids afforded diastereomerically pure secondary carbinols 8. Protection of the hydroxyl group and unmasking of the oxazolidine ring gave O-protected α-hydroxy aldehydes 11, which were immediately reduced to the corresponding 1,2-diols 12.
对映异构纯2-甲酰基的N-Boc-
1,3-恶唑烷7在83%的产率制备从stannyloxazolidine 4。在
路易斯酸的存在下,将格利雅(Grignard)加成化合物7的甲酰基,得到非对映体纯的仲
甲醇8。羟基的保护和
恶唑烷环的未掩蔽得到O保护的α-羟基醛11,将其立即还原为相应的1,2
-二醇12。