TY - JOUR
T1 - A comparison of the Wittig and Knoevenagel-Doebner reactions for the chain extension of aldoses
AU - Collins, Peter M.
AU - Overend, W. George
AU - Shing, Tony S.
PY - 1982/1/1
Y1 - 1982/1/1
N2 - Reaction conditions are described for the chain extension of 2,3 : 5,6-di-O-isopropylidene-D-mannose (1) with a Wittig ylide (2) to give the acyclic manno-octenoate (3) or the C-glycofuranosides (4 and 5) and with the Knoevenagel-Doebner reaction to afford the isomeric gluco-octenoate (6); the isomerisation proved to occur in the latter reaction provides an explanation for an anomaly in the literature and indicates that the C-glycosides (4 and 5) are formed by a Michael-type ring closure rather than via a betaine intermediate.
AB - Reaction conditions are described for the chain extension of 2,3 : 5,6-di-O-isopropylidene-D-mannose (1) with a Wittig ylide (2) to give the acyclic manno-octenoate (3) or the C-glycofuranosides (4 and 5) and with the Knoevenagel-Doebner reaction to afford the isomeric gluco-octenoate (6); the isomerisation proved to occur in the latter reaction provides an explanation for an anomaly in the literature and indicates that the C-glycosides (4 and 5) are formed by a Michael-type ring closure rather than via a betaine intermediate.
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U2 - 10.1039/C39820000297
DO - 10.1039/C39820000297
M3 - Article
AN - SCOPUS:0010683368
SN - 0022-4936
SP - 297
EP - 298
JO - Journal of the Chemical Society, Chemical Communications
JF - Journal of the Chemical Society, Chemical Communications
IS - 5
ER -