ORGANOBORANES FOR SYNTHESIS .15. B-ALLENYL-9-BBN - A HIGHLY REGIOSPECIFIC AND CHEMOSELECTIVE REAGENT FOR ALLENYLBORATION OF REPRESENTATIVE CARBONYL-COMPOUNDS, LEADING TO HOMOPROPARGYLIC ALCOHOLS AND AMINES
ORGANOBORANES FOR SYNTHESIS .15. B-ALLENYL-9-BBN - A HIGHLY REGIOSPECIFIC AND CHEMOSELECTIVE REAGENT FOR ALLENYLBORATION OF REPRESENTATIVE CARBONYL-COMPOUNDS, LEADING TO HOMOPROPARGYLIC ALCOHOLS AND AMINES
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DOI：
10.1021/jo00108a014
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发表时间：
1995-02-10
影响因子：
3.6
通讯作者：
RACHERLA, US
中科院分区：
文献类型：
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作者：
BROWN, HC;KHIRE, UR;RACHERLA, US
B-联烯基-9-BBN（11）与代表性羰基化合物如醛、酮、酰氯、羧酸酯和亚胺的反应干净地进行，其中联烯基部分经历转移到羰基或亚胺碳，联烯基到炔丙基重排，并且硼部分转移到羰基氧或亚胺氮。用碱性过氧化氢进行简单的氧化，以优异的产率形成相应的高炔丙醇和胺。醛、酮和亚胺以1：1的化学计量反应，而酰氯和羧酸酯与2当量的试剂反应。还探讨了代表性的醛、酮和酯对11的相对反应性。除了高度区域特异性之外，试剂11还具有显著的化学选择性。B-Allenyl-9-BBN可以区分空间位阻较小和较大的醛、酮和酯，使得在含有较少反应性官能团的复杂有机分子中所需羰基的清洁和选择性炔丙基硼化成为可能。
Reactions of B-allenyl-9-BBN (11) with representative carbonyl compounds, such as aldehydes, ketones, acid chlorides, carboxylic acid esters, and imines, proceed cleanly with the allenyl moiety undergoing transfer to the carbonyl or imine carbon, with allenic to propargylic rearrangement, and the boron moiety to the carbonyl oxygen or imine nitrogen. A simple oxidation with alkaline hydrogen peroxide results in the formation of the corresponding homopropargylic alcohols and amines in excellent yields. Aldehydes, ketones, and imines react in a 1:1 stoichiometry, while acid chlorides and carboxylic acid esters react with 2 equiv of the reagent. The relative reactivities of representative aldehydes, ketones, and esters toward 11 were also explored. Besides being highly regiospecific, the reagent 11 also possesses a remarkable chemoselectivity. B-Allenyl-9-BBN can distinguish between less and more sterically hindered aldehydes, ketones, and esters, making possible the clean and selective propargylboration of a desired carbonyl group in complex organic molecules containing less reactive functional groups.