Benzyloxyacetyl chloride

A multistep solid phase synthesis of (3-lactams with imines of benzaldehyde coming out from commercially available fluorinated a-amino acids has been reported in 2003 [77]. Using the Merrifield resin-bound imine [78, 79] in dichlor-omethane, the cycloaddition was carried out between -78°C and rt by addition of benzyloxyacetyl chloride in the presence of triethylamine. The resin cleavage using sodium methylate resulted in the two cis p-lactam derivatives (Scheme 20). 

C9H803 p-hydroxycinnamic acid, predominantly trans 501-98-4 500.48 43.931 2 16311 C9H9CI02 benzyloxyacetyl chloride 19810-31-2 491.59 43.076 2... 

In a similar manner, enantiopure l-f-Boc-3-TIPSO-4-CF3-P-lactam 14 was synthesized from benzyloxyacetyl chloride/triethylamine and (V-PMP-CF3-aldimine through [2+2] ketene-imine cycloaddition, enzymatic optical resolution (PS Amano lipase at... 

The j -lactam nucleus can also be assembled efficiently by a ketene-imine cycloaddition known as the Staudinger reaction. The reaction of chiral imine 759 with alkoxyketenes generated tfom benzyloxyacetyl chloride or acetoxyacetyl chloride affords cw-3,4-di-substituted )S-lactams 764a (75% yield) or 764b (61% yield) with diastereoselectivities greater than 95% [218]. 

Trifluoromethyl substituted aldimines react with a-benzyloxyacetyl chloride in the presence of triethylamine to give the CF3 substituted azetidinones in 50 % yields Also, A-o -(trimethylsilyl)methyl imines undergo cycloaddition with the oxazolidinone substituted ketene 269 to give the [2-1-2] cycloadducts 270 with excellent diastereomeric... 

A chiral quaternary carbon center via an addition-rearrangement reaction of 3,3-disubstituted allyl morpholine (61) and benzyloxyacetyl chloride (56) was successfully constructed with 300 mol% of chiral Mgl2 (60) complex, and the corresponding Claisen adduct (62) was obtained in 97% ee and 94 6 syn anti selectivity (Scheme 4.18). 

The Staudinger reaction of ketenes to aldimines is well known to provide cw-p-lactams. However, it had never been studied in the case of fluoroalkyl imines. The trifluoroacetaldimine 17a has been prepared by the usual route from the corresponding ethyl trifluoromethyl hemiketal and p-methoxyaniline. " Reaction of the benzyloxyketene, generated from a-benzyloxyacetyl chloride, with imine 17a, performed at 45 °C in CHjClj, provided the expected cis azetidinone 16a in 65 % yield (Scheme 8). In azetidinone 16a, the Vh.3,h-4 coupling constant of 5 Hz indicates the cis relative configuration. Coupling constants in parent non-fluorinated P-lactams have been reported to be 2 Hz for the trans isomer and 5-6 Hz for the cis one. Condensation of the aldimine 17b with the same ketene led to the cis P-lactam 16b in 72 % yield. The cis P-lactam 16c was obtained in a satisfatory yield (55 %) from the aldimine 17c (Scheme 8). 

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