4-hydroxy-1-piperidin-1-ylbutan-1-one

4-[tert-butyl(dimethyl)silyl]oxybutanal

(3E)-3-(naphthalen-1-ylmethylidene)oxolan-2-one

2-trimethylsilylethyl 2,4-dibromobutanoate

1-methyl-5-(oxolan-2-ylidene)pyrrol-2-one