Kinetic acetonation of sucrose: preparative access to a chirally substituted 1,3,6-trioxacyclooctane system

Abstract

44-3; paraformaldehyde, 50-00-0; l,3-bis(benzenesulfonyloxy)-2benzenesulfonamidopropane-2-14C, 78515-45-4; benzenesulfonyl chloride, 98-09-9; bromobenzene, 108-86-1; benzoic acid, 65-85-0; 2-benzylethylene oxide, 4436-24-2; ethyl a-phenylcyanoacetate, 4553-07-5; benzenesulfonyl-2-(bromomethyl)ethylenimine, 5120-12-7.

(2S,3S,4R,4a'R,5R,5a'R,11a'R,12′S,12a'R)-5-(Acetoxymethyl)-2′,2′,10′,10′-tetramethyloctahydro-3H,8′H-spiro[furan-2,7′-[1,3]dioxino[4′,5′:5,6]pyrano[3,2-d][1,3,6]trioxocine]-3,4,12′-triyl triacetate

“…406-408 K [lit. (Fanton et al, 1981) (Fanton et al, 1981) 173. 0, 171.6, 171.2, 170.0, 105.2, 101.6, 92.5, 90.7, 80.2, 79.5, 78.4, 76.3, 73.6, 70.6, 69.7, 64.5, 64.3, 62.7, 25.6, 24.1, 21.3, 21.1, 20.9 (4), 20 (9), 20.8 (one signal obscured or overlapping); IR (film) max 2998, 2939, 1742, 1371, 1221, 1151, 1131, 1069, 1047, 1034, 1017, 945, 894, 856, (4) 147Symmetry codes: (i) x þ 1; y þ 1; z; (ii) x À 1; y; z; (iii) Àx þ 1; y þ 1 2 ; Àz þ 1.…”

Regio- and Stereoselective Transformations of Sucrose at the Terminal Positions

“…The latter may be obtained as the sole product through the action on sucrose of an excess of 2-methoxypropene at elevated temperature (v. in Scheme 7). [35,36] Deprotection of the 4,6-acetal in 26 provides Ϫ in moderate yields Ϫ the monoacetal with the functionality at the 1Ј,2-position. [37] Scheme 7. i. acetone, H ϩ ; ii.…”

An Efficient Catalysed Ceric Ammonium Nitrate Acetonation Method for Carbohydrates

“…The identification of acetonation products: 2,1':4,6-di-O-isopropylidenesucrose 1, 4,6-O-isopropylidenesucrose 2 and 2,1':4,6-di-O-isopropylidene-6'-O-(1methyl-1-methoxyethyl)sucrose 3 (Scheme) was based on the comparison with their described NMR data of them and/or the data of the their acetyl derivatives. 6 The data shown in Table 1 indicate that the sucrose/CAN ratio appears to be very important, actually, with a 1:1 ratio higher acetonide yields than those of a 1: 0.2 ratio were achieved for short reaction time (6 h), but the opposite occurred for longer reaction time (25 h). This might be due to the decomposition of acetonides occurring with a 1:1 ratio, as indicated by the appearance on TLC of less polar products by increasing the reaction time.…”

“…Many catalysts have been used, and these reactions lead generally to the thermodynamically favoured products. 3,4 On the other hand, the formation of kinetically controlled products is usually obtained when DMP 5 or 2-alkoxypropene 6 in DMF, in the presence of p-toluenesulfonic acid (TsOH), are used as acetonating reagents.…”

“…Both in dry acetonitrile and nitromethane it gave mixtures of products which were less polar than the sucrose isopropylidene derivatives. Table 2 shows the products obtained applying the CAN promoted O-isopropylidenation method on some selected sugars as well as the yields of acetonation reaction obtained by 2,2-alkoxypropene 3c, 6,7,9,11,12 and by DMP 5d, 5a,8,10 in DMF at room temperature using TsOH as catalyst. A comparison of the data of Table 2 shows that yields of the CAN procedure are often higher than those of the two other methods and that the product distributions are more similar to those obtained by acetonation with DMP/TsOH rather than by 2-alkoxypropene/TsOH method, except for mannose.…”