作者:Mark C. Bagley、Richard T. Buck、S. Lucy Hind、Christopher J. Moody
DOI:10.1039/a704093h
日期:——
A new method for the synthesis of oxazoles, and in particular chiral non-racemic oxazoles derived from amino acids, has been developed. Thus, rhodium(II) catalysed reaction of diazocarbonyl compounds 6 and 11 in the presence of amides 8 and 10 results in regioselective insertion of the carbenoid into the amide N–H bond with formation of the β-carbonyl amides 9 and 12. Cyclodehydration of amides 9 and 12 using triphenylphosphine–iodine–triethylamine gives functionalised oxazoles 7 and 13. The oxazoles 13c and 13f were converted into the bis-oxazoles 17a and 17b by a second rhodium(II) catalysed regioselective N–H insertion reaction on the amides 15, followed by cyclodehydration.
开发了一种合成恶唑(特别是从氨基酸衍生的非外消旋手性恶唑)的新方法。因此,在酰胺8和10存在下,钌(II)催化的重氮羰基化合物6和11的反应导致卡宾类似物区域选择性地插入酰胺N-H键,形成β-羰基酰胺9和12。使用三苯基膦-碘-三乙胺对酰胺9和12进行环脱水反应,得到功能化的恶唑7和13。恶唑13c和13f通过在酰胺15上进行第二次钌(II)催化的区域选择性N-H插入反应,然后进行环脱水反应,被转化为双恶唑17a和17b。