用镁和溴代醇的羧酸酯反应合成羟基酮

看机化学 YouJi HUAXUE，1989，9拈 ～拈7 暂F兜叠讯 用镁和溴代醇的羧酸醋反应合成羟基酮 鲁乃聚·、徐良衡 (复旦大学化挚系，上海) j， i ． ’ I -， { ： I ’ 《j i# -． 囊一 ． 尊，羟基卣， gn删 反应 R e acti o 1． ns 。 ． The Bromoalkyl carboxylates with Magnesium Leading m ·：Synthe~ls of Hydroxyketones ： · ’ HUANG N ai-Ju●， X U Liang—Heng (Department ol Chemistry，Fudan University，Shanghai) Although the conventional Grignard reagent using magnesium and organic halide is well known，the featrians beiWeen magnesium and compounds sirhUh'aneousIy 曲dth曲ing a halo— gen and a fuhetional group which can react with Grignard reagents are rare1v studiedt¨ ． In this pape~we report the 7eactions f bromoalkya carboxylie , vst嘟 with magnesium lead- ing to the synthesis of hydroxyketones．Bromoalkyl earboxylic e ers CaEt be easily prepared from the corresponding cyclic acetaIs when refluxcd with N-bromosuccinimide (NBS)jn CCI4 and in the presence of 2，2 一azobisisobutyronitrile (AIBN)【 ．The~synthetic sequence is shown in sche~-e 1．The results of this study are summarized in the Tab 1． A ll products ⋯⋯⋯一日— 乏0／l H cH|} 一一、oH I l№ n ：一 ， ￡ R·alk l 0P arVI ^·s．1 Schem a 1 were purified by distillation or recrystallization and characterized by IR ， N M R and elemen． tal analysis．Thus，the above synthetic approach of 4 provides a facile and mlid condition for the synthesis of hydroxyketones fro m aldehydes． 1989年 3月 26日收稿，1989年 4月 25旨修同。 维普资讯 http://www.cqvip.com 第5期 用镁和溴代醇的泼酸酯反应合成羟基醌 437 Aeetal m．P．Or Bromoalkyl Yield b．p．of Hydroxy- Yield of m．P．orb． Entry b．P．of carboxylates of(5) (5)(℃ ／ ketones (4) P．0f ‘4》 (2) (℃ ／ (2) mmHg) (4) ( ) ( ／mmHg)， mmHg) (5) ( ) - ◎-《] 0 ，、一 85 102～ 88 120～ 一 0 _ll。I 靠 J ， 105／1 ● b 00 88 。 l26～ l 85 n9～ 。 0 ，、 88 128 l ’ j r j c 删 88 。 —0 m 1 28～ t， 。 69 ll 、：： 一 100 1 83 1 30／L 一 ' d 。 ，、，e 78 1 5G～ 。 72 le2～ e c 120—。 c- ．72 158／】 l 163l 152～ c 一 82 ’ IB6～ 。 22 ／ 】54／1 l67 ， 一t ： ， 一 l 《=》 一 85 11"2 ．。0 90 tl5～ 1l4 l 1l7 |_ 。 t一 2 6 84～ r、， 63 104 lee／1． 、 L t — 89 6e～ —、 、^ ／ ¨H 56 79—一 ～ 一 。 t咖 ’ 45／1 86／L h — 0 ； ，，、- — ^、耻 _ 7l，2 81／i · 0扎 ·r 0 训．1，Ranos det。ermine y GC 嗨 献 F l~ocedure： (The starting acetals and bromoalkyl ca~ ． boxylic esters were prepared according to the litera— ture ．【2】 ‘ Preparation of hydMx to1ld(面婀 a in Tab 1．) In a flask place 3 ．6g (0．i5med)of magnesium turnings and l0mL anhydrous ether． To a m ixture of 15 ．7 g 0 08too1) of the bromoethyl eSter (3 a) and 30mL of anhydrous ethe r，0．5 mL 1．2-dibromoethane was added dropwise to maintain the solution in a gentle boiling， ． After 0oO1ing the mixture was slowly poured into a cold mixture of saturated N C1 so1ution and 25 g of ice，After separation and extraction with ethe r the combined organic 虹yer was wae&ed succes~ively witlt 10 Na2CO3 solution and-Hzb dried on Mgs0‘ and li 她 时 啦 *vaperation of the Sblvent~,tJle residue was distilled'umlcr vaculAI~．1O ． 5g (aS yield)of!the product w褥 collected as a colorless oil．b．P．120~122／1 mmHg；v⋯ ： 砷 ，3030 1680(strong) 30 cm～．6H：(CC1。)：7．8(2 H m)，7，4(3 H，m)，3．8 (2H，t)，3．I(2H ，t)，2．5(I H，s)ppm． 孵 mag#es~um，esters，hydroxyketon，Grignard reaction ． I Referenee$ 维普资讯 http://www.cqvip.com