Reactions of 2,2,2-trichloroethyl 6-diazopenicillanate with aromatic aldehydes. X-Ray crystal structures of (3S,8aS)-2,2,2-trichloroethyl 2,3-dihydro-6-(4-methoxyphenyl)-2,2-dimethyl-5-oxo-5H,8aH-thiazolo[2,3-b][1,3]oxazine-3-carboxylate and (2S,5S)-2,2,2-trichloroethyl-4-formyl-2-(4-methoxyphenyl)-