A convenient and high yielding procedure for the preparation of isoselenocyanates. Synthesis and reactivity of -alkylselenocarbamates.
作者:Derek H.R. Barton、Shyamal I. Parekh、Mahmoud Tajbakhsh、Emmanouil A. Theodorakis、Tse Chi-Lam
DOI:10.1016/s0040-4020(01)80783-3
日期:1994.1
A high yielding one pot procedure for the preparation of isoselenocyanate from the corresponding formamide is reported. Various aromatic and aliphatic primary amines were employed in order to prepare the isoselenocyanates to establish the generality of the procedure. O-Alkylselenocarbamates of various primary, secondary and tertiary alcohols were synthesized and their stability and comparative reactivity
Steroidal sulphur compounds. Part II. Pyrolysis, absolute configuration, and optical rotatory dispersion of steroidal methyl sulphoxides
作者:D. Neville Jones、M. J. Green、M. A. Saeed、R. D. Whitehouse
DOI:10.1039/j39680001362
日期:——
sulphur in 3β-acetoxy-(R)- and (S)-5α-methylsulphinylcholestane was also determined by an interpretation of intramolecular reactions involving the sulphoxide group. Two Cotton effects of opposite sign near 210 and 230 mµ occur in the o.r.d. spectra of the sulphoxides. Their relevance to chirality at sulphur and to restricted rotation about a C–S bond is discussed.
在手性硫([R )-和(小号)-4β甲基亚磺酰基5α-胆甾烷,(- [R )-和(小号)-5α-methylsulphinylcholestane,和3β乙酰氧基- ([R ) -和(小号)-5α-甲基亚磺酰基胆甾烷已通过热解法测定。碱催化的4β-亚砜氧化物差向异构化生成(R)-和(S)-4α-甲基亚磺酰基-5α-胆甾烷。还通过解释涉及亚砜基团的分子内反应来确定3β-乙酰氧基-(R)-和(S)-5α-甲基亚磺酰基胆甾烷中硫的手性。210和230 m µ附近的两个相反符号的棉花效应发生在亚砜的奥德谱中。讨论了它们与硫的手性和与C–S键的受限旋转的相关性。
Efficient method for inversion of secondary alcohols by reaction of chloromethanesulfonates with cesium acetate
作者:Takeshi Shimizu、Sayoko Hiranuma、Tadashi Nakata
DOI:10.1016/0040-4039(96)01333-0
日期:1996.8
Inversion of a variety of secondaryalcohols using the (chloromethylsulfonyl)oxy group as a favorable leaving group with cesiumacetate in the presence of 18-crown-6 has been performed to give the inverted acetates in high yields.
An efficient method for the reductive transposition of allylic alcohols
作者:Andrew G Myers、Bin Zheng
DOI:10.1016/0040-4039(96)00965-3
日期:1996.7
Mitsunobu reaction of allylicalcohols with o-nitrobenzenesulfonylhydrazine (NBSH) as nucleophile proceeds at −30 °C with invertive displacement; warming the resultant N-allylic sulfonylhydrazine derivative to 23 °C then leads to allylic diazene formation followed by sigmatropic elimination of dinitrogen. This one-step method for reductive 1,3-transposition is shown to be efficient and highly regio- and