Organic transformations that result in the formation of multiple covalent bonds within the same reaction are some of the most powerful tools in synthetic organic chemistry. Nitrosocarbonyl hetero-Diels–Alder (HDA) reactions allow for the simultaneous stereospecific introduction of carbon–nitrogen and carbon–oxygen bonds in one synthetic step, and provide direct access to 3,6-dihydro-1,2-oxazines. This Review describes the development of the nitrosocarbonyl HDA reaction and the utility of the resulting oxazine ring in the synthesis of a variety of important, biologically active molecules.

Significantly improved Bouveault-Blanc conditions for ester reduction have been developed using sodium in silica gel (Na-SG), a free-flowing powder that can be easily handled in the open atmosphere. Primary alcohols were prepared in excellent yield from a variety of aliphatic esters under mild reaction conditions. The chemistry presented here is far safer than the classic Bouveault-Blanc reduction and is competitive with more modern hydride reduction methods.

Organische Transformationen, die in einem einzigen Reaktionsschritt mehrere kovalente Bindungen aufbauen, zählen zu den leistungsfähigsten Verfahren in der organischen Synthese. Hetero‐Diels‐Alder(HDA)‐Reaktionen von Nitrosocarbonylverbindungen ermöglichen die stereospezifische Einführung von Kohlenstoff‐Stickstoff‐ und Kohlenstoff‐Sauerstoff‐Bindungen in einem einzigen Syntheseschritt und bieten einen direkten Zugang zu 3,6‐Dihydro‐1,2‐oxazinen. In diesem Aufsatz werden die Entwicklung der Nitrosocarbonyl‐HDA‐Reaktion und der Nutzen der daraus erhältlichen Oxazinringe bei der Synthese verschiedener wichtiger biologisch aktiver Verbindungen beschrieben.

The addition of azides to acylnitroso hetero-Diels-Alder cycloadducts derived from cyclopentadiene affords exo-triazolines in excellent yield. The reaction is greatly affected by the level of alkene strain, while sterically demanding azides do not hinder the reaction. Conversion of the triazolines to aziridines is also described.

An unusual bicyclic hydroxamate resulted from C-O bond cleavage of acylnitroso hetero-Diels-Alder cycloadducts when treated with catalytic Brønsted acids under anhydrous conditions. Similarly, the formation of a nitrone was observed using one equivalent of triflic acid.