Zur stereoselektiven Synthese von 1‐O‐Alkyl‐3‐O‐benzyl‐sn‐glycerolen und 1‐O‐Alkyl‐2‐O‐methyl‐3‐O‐β‐D‐glycosyl‐sn‐glycerolen

Abstract

Starting with D-mannitol, the yield of the synthesis of 3-0-benzyl-sn-glycerol (1) could be improved. The regioselective alkylation of 1 at the primary hydroxy group to the 1-0-alkyl-3-0-benzyl-sn-glycerols 3 was achieved by using the dibutylstannylene protecting group. The 1-0-alkyl-2-0-methyl-snglycerols 4, readily obtainable from 3, were successfully glycosylated under the conditions of the Koenigs-Knorr reaction to give l-O-alkyl-2-O-methyl-3-O-~-~-glycosyl-sn-glycerols.

Regioselective synthesis of long-chain ethers and their sulfates derived from methyl β-d-galactopyranoside and derivatives via dibutylstannylene acetal intermediates

“…They have been used to introduce long-chain esters. 17 They have also been used to alkylate glycerol derivatives at primary positions in moderate to good yields [18][19][20] and to alkylate xylitol at primary positions in moderate yields. 21 In reactions of dibutylstannylene acetals, one of two oxygen atoms reacts preferentially.…”

Control of regioselectivity in reactions of dialkylstannylene acetals. Part I. A dramatic reversal of regioselectivity in mono-p-toluenesulfonation reactions

“…It seems likely that acetonitrile acts as a nucleophile towards the stannylene acetal dimers and releases coordinated monomers so that at least part of the reaction in acetonitrile occurs through these monomeric intermediates. In DMF (17,20), pyridine (1 1, 22) or 4-dimethylaminopyridine (14), amines (12,13), and methanol (12,13), all of which are more nucleophilic than acetonitrile as measured by, for instance, Gutmann's donor number (3 l), greater regioselectivity is obtained for reaction at the primary centre.…”

Synthesis of ether lipids: natural compounds and analogues

“…First, they reported an asymmetric synthesis of the aglycone part starting with the asymmetric bis-hydroxylation of allyl 4-methoxyphenyl ether 65.1 to produce 65.2 ( Figure 65A ). The opening of the 1,2- O -stannylidene intermediate, previously reported by Liefländer [ 209 ], is regioselective but it is not fully controlled leading to the formation of 65.3 (90%) and 65.4 (8%), required a separation by chromatography. Then, the methylation of the sn -2 alcohol function produced 65.5 and the deprotection of the primary alcohol with cerium(IV) ammonium nitrate (CAN) produced the key intermediate 65.6 in 95% yield.…”

“…In 1991, the group of M. Liefländer reported the synthesis of neutral analogues of edelfosine with the replacement of the phosphocholine polar group with either glucuronic acid methyl ester 63.8 , cellobiose 63.9 or maltose 63.10 ( Figure 63A and B) [ 209 ]. The synthesis ( Figure 63A ), illustrated with the preparation of glucuronic acid methyl ester 63.8 , started with the synthesis of the diether 63.5 which is a key intermediate.…”

“… A) Synthesis of glucuronic methyl ester 63.8 ; B) structure of cellobiose 63.9 and maltose 63.10 analogues prepared following the same protocol [ 209 ]. …”