Concise Synthesis of the Phosphoglycerylated Tetrasaccharide Repeating Unit of the Capsular Polysaccharide of Streptococcus pneumoniae Serotype 11 A

Abstract

A concise convergent synthetic strategy has been developed for the first synthesis of the glycerol phosphate‐containing tetrasaccharide repeating unit of the capsular polysaccharide of S. pneumoniae 11 A strain in very good yield. A stereoselective [2+2] block glycosylation strategy has been adopted for the synthesis of the tetrasaccharide derivative. All glycosylations were highly stereoselective with satisfactory yield.

Recent progress in chemical synthesis of bacterial surface glycans

“…Synthetic targets chemically obtained include repeating units (RUs) and related oligomers or analogs of CPSs (1-25) [10,12,[19][20][21][22][23][24][25][26][46][47][48][49][50][51][52][53][54][55][56][57][58][59], LPSs and LOSs [28][29][30][31][32][33][34][35][36][37][60][61][62][63][64][65][66][67][68][69][70][71][72], cell wall polysaccharides (50)(51)(52)(53)…”

“…The CPS oligosaccharides and analogs obtained (Figure 2A) include those from Hib (1) [19]; S. pneumoniae (Sp) serotypes ST1 (2) [20] ** , ST2 (3) [10], ST3 (4)(5) [21] ** , ST5 (6) [46], ST8 (7a-7d) [12] ** , ST11A (8) [22], and ST12F (9) [47]; group B Streptococcus (GBS) or Streptococcus agalactiae types Ia (10) [23], II (11) [24], VII (12) [25]; carbapenem-resistant Klebsiella pneumoniae (CR-Kp) (13) [26]; A. baumannii K47 (14) [48]; S. aureus types 5 (15) [49,61] and strain M (16) [50]; B. mallei (17) [51,52]; C. jejuni RM1221 (18) [53] ** and 81-176 (19) [54]; Bacteroides fragilis CPS PS A1 RU (20) [55]; Morganella morganii (21) [56]; C. bolteae (22) [27] ** , K. kingae KK01 (23) [57], C. psychrerythraea 34H (24) [58] and S. typhi (25) [59]. Among these, compounds 2, 20, 21, and 45 are repeating units of zwitterionic polysaccharides (ZPSs).…”