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Organoboron‐Disaccharides, III. Regioselective O ‐Ethylboranediylation of Octakis‐ O ‐(diethylboryl)sucrose
Author(s) -
Taba Kalulu M.,
Köster Roland,
Dahlhoff Wilhelm Volker
Publication year - 1987
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.198719870355
Subject(s) - chemistry , sucrose , acetylacetone , chloride , reagent , methanol , medicinal chemistry , nuclear chemistry , organic chemistry
Octakis‐ O ‐(diethylboryl)sucrose ( 2 ), easily obtained from sucrose ( 1 ), reacts with ethylboron reagents [ethyldiboranes(6), triethylboroxin, 1,3‐bis(2,2‐dimethylpropanoyloxy)‐1,3‐diethyldiboroxane (BEPDIB), ethyldimethoxyborane] to give various mixtures of 3,3′,4′,6′‐tetrakis‐ O ‐(diethylboryl)‐2,1′:4,6‐di‐ O ‐(ethylboranediyl)sucrose ( 4 ) and 2,3,1′,3′,4′,6′‐hexakis‐ O ‐(diethylboryl)‐4,6‐ O ‐(ethylboranediyl)sucrose ( 3 ). The O ‐diethylboryl groups were selectively removed with acetylacetone to give mixtures of 5 and 6 . After O ‐acetylation to mixtures of 7 and 8 and deborylation with methanol, 2,3,1′,3′,4′,6′‐hexa‐ O ‐acetylsucrose ( 9 ) and 3,3′,4′,6′‐tetra‐ O ‐acetylsucrose ( 10 ) were separated by HPLC. 10 reacts with activated triethylborane to give 11 and with mesyl chloride to give 12 .