Enantiospecific synthesis of (+)-retronecine, (+)-crotonecine, and related alkaloids
作者:J. Grant Buchanan、Veerappa B. Jigajinni、Gurdial Singh、Richard H. Wightman
DOI:10.1039/p19870002377
日期:——
Reaction of 2,3-O-isopropylidene-D-ribose (8) with diallylzinc gave a triol, which on treatment with periodate was converted into 5,6,7-trideoxy-2,3-O-isopropylidene-L-ribo-hept-6-enofuranose (10)(86%). Reaction with hydroxylamine hydrochloride in pyridine gave an oxime (11), which was treated with methanesulphonyl chloride in pyridine to yield 5,6,7-trideoxy-2,3-O-isopropylidene-4-O-methylsulphon
2,3-反应ö异亚丙基d -核糖(8)配有diallylzinc得到的三醇,其用高碘酸盐处理转化为5,6,7-三脱氧-2,3- ö异亚丙基大号-核糖-庚6-呋喃呋喃糖(10)(86%)。在吡啶中与盐酸羟胺反应,得到肟(11),将其用甲磺酰氯处理,在吡啶,得到5,6,7-三脱氧-2,3- ö异亚丙基-4- ö -methylsulphonyl-大号-核糖-庚-6-乙腈(12)(总体占87%)。用氢化铝锂还原并环化,然后用氯甲酸苄酯处理,得到(2 R,3 S,4 R)-2-烯丙基-1-苄氧基羰基-3,4-异丙基二烯二氧基吡咯烷(14),将其氧化并随后与重氮甲烷反应得到(2R,3S,4R)-(1-苄氧基羰基-3,4-异丙基二烯二氧基吡咯烷二-2-基)乙酸甲酯(15b)(35%)。