Stereoselective Synthesis of Highly Substituted γ-Lactams by the [3+2] Annulation of α-Siloxy Allylic Silanes with Chlorosulfonyl Isocyanate
摘要:
A stereoselective synthesis of gamma-lactams by the [3+2] annulation of alpha-siloxy allylic silanes with N-chlorosulfonyl isocyanate (CISO2NCO) was developed. The use of these allylic silanes allowed for further diastereoselective substitution of the resultant N,O-acetal to give highly substituted gamma-lactams. Oxidation of the silyl group afforded access to complex beta-hydroxy-gamma-lactams.
Lewis Acid-Assisted Photoinduced Intermolecular Coupling between Acylsilanes and Aldehydes: A Formal Cross Benzoin-Type Condensation
作者:Kento Ishida、Fumiya Tobita、Hiroyuki Kusama
DOI:10.1002/chem.201704776
日期:2018.1.12
by Lewis acid is highly important to realize this reactionefficiently, otherwise the yield of the desired coupling products were significantly decreased. Noteworthy is that a formal cross benzoin‐type reaction using acylsilanes was achieved under Lewis acidic conditions. This is the first example of Lewis acid‐catalyzed reaction of photochemically generated siloxycarbenes with electrophiles.