Tin(II) chloride dihydrate: A mild and efficient reagent for cleaving acetals.
摘要:
Tin(II) chloride dihydrate (SnCl2.2H2O) efficiently converts conjugated dioxolanes, and both dimethoxy and diethoxy acetals to aldehydes (84-98%). Similarly, nonconjugated dimethoxy and diethoxy acetals are also efficiently converted to aldehydes (84-94%). Conjugated pyrans and nonconjugated dioxolanes, however, are only converted to aldehydes in 17-38% yields.
Reversing the Regiochemical Course of 1,3-Dipolar Cycloaddition of Nitrile oxides by Modification of Dipolarophiles
作者:Akio Kamimura、Kenzi Hori
DOI:10.1016/s0040-4020(01)85282-0
日期:1994.1
Cycloaddition to the acetal derivatives preferentially gave the regioisomer bearing acetal group on C(4) position. While the opposite regioselectivity was observed for the cycloaddition to dithioacetal derivatives, where the sulfur functional group was mainly located at C(5) position. Theoretical studies on these regiochemical courses showed the C(5) orientation of dithioacetal groups to be directed