Ring Cleavage and Successive Aldol Reaction of 3-[(Trialkylsilyl)methyl]cyclobutanones
摘要:
3-[(Trialkylsilyl)methyl]cyclobutanones reacted with aldehydes by activation with titanium(IV) chloride to give acyclic beta,gamma-unsaturated beta'-hydroxyketones.
A transition‐metal‐free approach to the alkylation/arylation of benzoxazole was developed by employing Tf2O‐activated‐amide as the alkylating/arylating reagent. The mild reaction conditions, and particularly insensitivity to air and water, further enhance the synthetic potential in pharmaceutical synthesis.
Amide Formation in One Pot from Carboxylic Acids and Amines via Carboxyl and Sulfinyl Mixed Anhydrides
作者:Bartosz K. Zambroń、Srinivas R. Dubbaka、Dean Marković、Elena Moreno-Clavijo、Pierre Vogel
DOI:10.1021/ol401053y
日期:2013.5.17
An efficient method has been developed for the preparation of yet unknown acyclic mixedanhydrides of carboxylic and sulfinic acids. Sterically hindered 2-methylbut-3-ene-2-sulfinyl carboxylates add primary and secondary amines preferentially onto the carbonyl moieties realizing a new method for the one-pot preparation of carboxamides. It uses 1:1 mixtures of carboxylic acids and amines without a base
cycloaddition between 3-ethoxy-2-alkylcyclobutanones and nitrosobenzene proceeded by activation with Me 3 SiOTf to afford 6-alkyl-2-phenyl-2 H -1,2-oxazin-5(6 H )-one by regioselective cleavage of the more substituted C2–C3 bond of the cyclobutanone ring. On the other hand, reactions of 3-phenylcyclobutanones and 2-benzyloxycyclobutanone with nitrosobenzene gave γ,δ-unsaturated and cyclic hydroxamic acid derivatives
3-乙氧基-2-烷基环丁酮和亚硝基苯之间的正式[4+2]环加成反应通过用Me 3 SiOTf活化得到6-烷基-2-苯基-2 H -1,2-恶嗪-5(6 H )-one通过区域选择性裂解环丁酮环上更多取代的 C2-C3 键。另一方面,3-苯基环丁酮和2-苄氧基环丁酮与亚硝基苯的反应分别通过环丁酮C1-C2键的断裂产生γ,δ-不饱和和环状异羟肟酸衍生物。
Transition-metal-free multinitrogenation of amides by C–C bond cleavage: a new approach to tetrazoles
regioselective synthesis of 1,5-disubstituted tetrazoles has been developed. By means of electrophilic amide activation, and further C–C bond cleavage and rearrangement, a diverse set of functionalized 1,5-DST derivatives were selectively constructed under mild conditions. As showcased in the mechanisms, the chemoselectivity is easily switched by the selection of the starting materials in the reaction.