1.A study was made of the addition of triethyl orthoformate to someα- andβ-substituted vinyl ethers and 1-ethoxycyclohexene in presence of various catalysts; this permitted the synthesis of bis [diethyl acetals] of variousβ-dicarbonyl compounds (substituted malonaldehyde and acetoacetaldehyde).2.The previously undescribed bis [diethyl acetals] of methyl-, isopropyl-, and dimethyl-malonaldehydes, 2-methylacetoacetaldehyde, and 2-oxocyclohexanecarboxaldehyde were prepared and their structures were proved.3.The condensation of orthoacetic ester with ethyl vinyl ether in presence of a mixed catalyst (boron trifluoride etherate and zinc chloride) was carried out; as a result acetoacetaldehyde bis [diethyl acetal] was obtained.4.The reactions of orthoformic ester with diketene and with styrene were studi