Reaction SMILES: [Si]([O:8][C@H:9]([C:42]1[CH:47]=[CH:46][C:45]([F:48])=[CH:44][CH:43]=1)[CH2:10][S:11][C@H:12]1[C:15](=[O:16])[N:14]([C:17]2[CH:22]=[CH:21][C:20]([C:23]#[C:24][CH2:25][NH:26][S:27]([CH3:30])(=[O:29])=[O:28])=[CH:19][CH:18]=2)[C@@H:13]1[C:31]1[CH:41]=[CH:40][C:34]([O:35][CH2:36][C:37](O)=[O:38])=[CH:33][CH:32]=1)(C(C)(C)C)(C)C.Cl.[NH2:50][CH2:51][C:52]([O:54]C)=[O:53].CN1CCOCC1.CN(C(ON1N=NC2C=CC=CC1=2)=[N+](C)C)C.[B-](F)(F)(F)F.C(N(CC)CC)C.[Li+].[Cl-]>C(Cl)Cl.C1(C)C=CC=CC=1.C(O)(=O)C.O.CC#N>[F:48][C:45]1[CH:46]=[CH:47][C:42]([C@@H:9]([OH:8])[CH2:10][S:11][C@H:12]2[C:15](=[O:16])[N:14]([C:17]3[CH:18]=[CH:19][C:20]([C:23]#[C:24][CH2:25][NH:26][S:27]([CH3:30])(=[O:28])=[O:29])=[CH:21][CH:22]=3)[C@@H:13]2[C:31]2[CH:32]=[CH:33][C:34]([O:35][CH2:36][C:37]([NH:50][CH2:51][C:52]([OH:54])=[O:53])=[O:38])=[CH:40][CH:41]=2)=[CH:43][CH:44]=1
Reactant: CC(C)(C)[Si](C)(C)O[C@@H](CS[C@H]1C(=O)N(c2ccc(C#CCNS(C)(=O)=O)cc2)[C@@H]1c1ccc(OCC(=O)O)cc1)c1ccc(F)cc1
Reactant: COC(=O)CN
Agent: CN(C)C(On1nnc2ccccc21)=[N+](C)C
Agent: Cl
Agent: F[B-](F)(F)F
Solvent: CC(=O)O
Solvent: ClCCl
Solvent: CC#N
Product: CS(=O)(=O)NCC#Cc1ccc(N2C(=O)[C@H](SC[C@H](O)c3ccc(F)cc3)[C@H]2c2ccc(OCC(=O)NCC(=O)O)cc2)cc1
Reaction time: 0.08 h

Procedure:
{4-[(2R,3R)-3-{[(2R)-2-{[tert-butyl(dimethyl)silyl]oxy}-2-(4-fluorophenyl)ethyl]thio}-(4-{3-[(methylsulfonyl)amino]prop-1-yn-1-yl}phenyl)-4-oxoazetidin-2-yl]phenoxy}acetic acid (Method 8) (19.4 mg, 0.027 mmol) (19.0 mg, 0.020 mmol) was dissolved in DCM (2 ml). Methyl glycinate hydrochloride (4.1 mg, 0.033 mmol) and N-methylmorpholine (6 μl, 0.059 mmol) were added and the reaction mixture was stirred for five minutes. TBTU (9.5 mg, 0.029 mmol) was added and the mixture was stirred for 2 hours. The solvent was removed under reduced pressure. LC-MS confirmed the formation of the methylester and TBDMS-ether of the title compound. M/z: 782.55 (M−1). The residue was suspended in MeCN (1 ml). Triethylamine (27 μl, 0.19 mmol), water (7 μl) and LiCl (24.8 mg, 0.58 mmol) were added and the reaction mixture was stirred at 35° C. overnight. Additional triethylamine (15 μl, 0.11 mmol) and water (15 μl) were added and the reaction mixture was stirred at 35° C. for 5 hours. Additional MeCN (1 ml) was added and the reaction mixture was stirred overnight. The mixture was purified with preparative HPLC on a C8 column, UV 235/285 nm. A gradient from 20 to 85% MeCN in 0.1M NH4OAc buffer was used as eluent. Most of the MeCN was removed under reduced pressure and the residue was acidified to pH 3 and extracted from DCM. The phases were separated and the organic phase was passed through a phase separator. The solvent was removed under reduced pressure. The residue was dissolved in water and MeCN and lyophilised. LC-MS confirmed the formation of the TBDMS-ether of the title compound, M/z: 768.60 (M−1). The residue was dissolved in acetic acid (1 ml). Water (100 μl) and LiCl (27.6 mg, 0.65 mmol) were added and the reaction mixture was stirred overnight. The acetic acid was co-evaporated with toluene. The residue was purified with preparative HPLC on a C8 column. A gradient from 20 to 75% MeCN in 0.1M NH4OAc buffer was used as eluent. Most of the MeCN was removed under reduced pressure and the residue was lyophilised to give the title compound. H-NMR (400 MHz, DMSO-d6) 2.93 (d, 2H), 2.98 (s, 3H), 3.47 (d, 2H), 4.01 (s, 2H), 4.32 (d, 1H), 4.50 (s, 2H), 4.72 8t, 1H), 5.10 (d, 1H), 7.00 (d, 2H), 7.11 (t, 2H), 7.21 (d, 2H), 7.32-7.42 (m, 6H), 7.79 (b, 1H). M/z: 654.43 (M−1).